This part of the quest is purely extra setup for the fallout later. Other than bringing Marle to gain entry to the castle in the first place, you can skip it entirely, and rest of the events are unaffected. Actually, it's kind of sneaky... the game sets things up to look like you're supposed to take Marle on a sidequest to reconcile with her father, when you really need to do something completely different that at first seems to be entirely unrelated.

Soldier: !!
It-it's the terrorist gang!!

Everyone looks startled (except the Magus, who doesn't react at all), and all of the following in the active party speak before being chased out of the castle:

Frog: Who, what?
Terrorists?!

Bringing her along works better (at any point after defeating the Magus in the Middle Ages; prior to that she insists on leaving immediately).

The chancellor runs up to Marle from the direction of the throne room. Let's hope he's less of a jerk this time.

Chancellor: We've been worried, lady Marledia!
Your chancellor understands your feelings
quite well, lady Marledia.
The king places his kingdom above all else.
Yes, even when your mother, Queen Ariche,
passed away...

CHANCELLOR: I've been worried,
Princess!
I understand your pain.
But the king really only cares about
his realm...
Yes, even when your mother, Queen
Aliza passed away, he worked all
day!

Marle: Mother!?

Marle: No one could do that!
It's inhuman!

He turns away.

Chancellor: No, no, it's nothing.

CHANCELLOR: Oh, child, it's ancient
history now...

Marle runs around in front of him insistently.

Marle: Tell me!

Marle: Tell me more!

He turns away again.

Chancellor: It is difficult to say this, but...
Lady Ariche had been sickly to begin with
when her condition took a sudden turn.
Lady Ariche said that she wished to see
the king one last time, but the kng......

CHANCELLOR: This may be difficult...
Well, Queen Aliza's condition suddenly
changed for the worst.
She desperately wanted to see the
king one last time, but he couldn't
find the time to drop by...

Chancellor: Busy with official work or not,
he came not to lady Ariche's side...
As a young lady Marledia watched over her,
not understanding the concept of death...

CHANCELLOR: Said he had some work to
do...
But knowing nothing about death,
you waited faithfully by your
mother's side...

Chancellor: Lady Ariche passed
away...
Why, it's almost fair to say the
king killed lady Ariche...

CHANCELLOR: Aliza passed away in
sorrow...
It's as if the king indirectly killed
her... Such a shame...

Marle: ...!!
Father... did that to mother...

Marle: WHAT...!!
Father KILLED?
...MY MOTHER...?!!

He finally faces her.

Chancellor: Dear me, what have I done!?
Pay me no mind, lady Marledia!

CHANCELLOR: But what do I know!
There are reasons for everything,
right dear?

Chancellor: Now! You've returned at long last.
Please do stop and see the king.

CHANCELLOR: Now...so glad to see you
back again.
Please go and visit the king.

He leaves. Well, that certainly wasn't suspicious at all. There is some good news, though.

Crono's lawyer is in the barracks with several of the castle's soldiers.

口聞き appears to be a typo for 口利き (kuchi kiki), which in this context basically means he vouched for them.

That would be Crono's trial.

It's good to know Crono has some support. A soldier elsewhere goes as far as to say that...

Maybe it's not the best idea to go along with this, but let's have Marle talk to the king anway.

King: Oh, Marledia...

KING: Oh!
Nadia...

King: Wh-what did you come back for!?
Surely you're not here to see me!

KING: W, what do you want!
I'm not giving in to your demands!

Marle: ...

Marle: ......

King: What's that look for!?
You're the one who's running away!
And, come to think of it, bringing
such a bizarre lot into the castle...
Are you trying to start a circus!?

KING: It's your fault for leaving the
castle!
And letting these...hoodlums in here.
You might as well beg for bread on
the street corner!

Not a circus, exactly. He's referring to an over-the-top form of public advertising involving flashy outfits and various instruments. You could probably compare it to having a guy in a hot dog suit standing on the corner to promote a new diner.

Marle: How can you say that to my friends!?

Marle: Stop it!
They're my friends!

King: People like that as friends?
I could never justify that to the
Guardia royal family ancestors!

KING: They're a disgrace to this family!

Are we talking about the same ancestors who treat them, Crono and Frog in particular, as heroes?

Marle: You care less about me...

Marle: Father, you, you...

She turns away, arms crossed.

Marle: Less about me or mother!
Than your precious Guardia Kingdom!!

Marle: You care more about your country than me...or mother!!

King: What...?

KING: What...?

She whirls to point accusingly at him.

Marle: You're the one who killed mother!

Marle: You, ...you killed mother!

The music stops cold. He rises to his feet.

King: !!

KING: !!

King: Get OUT!
Never show yourself in front of me again!

KING: Get... OUT OF HERE this instant!!!
I never want to see your face again!

Marle: I wouldn't come even
if you hadn't said so!

King: I consider us neither parent nor child!
Do as you please!!

KING: We're no longer family!
Do as you wish!!

King Guardia storms out of the room, but the chancellor has an evil glint in his eye...

...though he acts appropriately distressed if spoken to after the scene.

The king can be found staring at the wall in his room in the west tower at this point, but he's not in a talkative mood.

However, after they check in on him, the chancellor suddenly decides to "help" again.

The idiom 目がない (me ga nai, literally "doesn't have eyes") means being fond of something to the point of being unable to think rationally about it.

A series of clues leads to a source of Hyper Jerky. Buying some and having Marle bring it to King Guardia finally prompts a reaction.

King: ......
A gift, from you?

KING: ......
For me?

Again, the music stops cold.

King: Urgh...
Giving me something so incredibly spicy when
you know quite well I have high blood pressure...!

KING: How dare you...?!
Giving me something this rich when
you KNOW I have high cholesterol...!

Do spicy food and high blood pressure have a connection? That's not something I'm familiar with, but maybe they do.

"Strange Happening" starts playing as Marle looks shocked.

King: I will not tolerate any more!
You've made it quite clear just
how much you hate me!

KING: This is the last straw!
Now I know how you REALLY feel!

King: Leave! I don't care where!
Never show yourself again!!

KING: Leave!
NOW!!!!
Never show your face here again!!

The party is ejected from the castle. No one stops them from reentering, but forget about getting back into the king's room.

Well, if that went as planned, it's certainly not the plan of anyone Marle wants to be friends with.

Toma the explorer is at the bar. He seems to frequent them, doesn't he?

Toma: Yo, {char1}.
I finally found a lead on the
Prismatic Shell.
But just this once, I'm getting
a really bad sort of feeling.
Oh yeah, I'll leave this with you.

TOMA: Hey {char1}, I've finally got a
lead on the Rainbow Shell.
But there's something odd going on...
Oh, can you hang on to this for me?

Toma: If I die, pour this sake on my grave.
...keh, it's like I'm jinxing myself.

TOMA: If I don't return, come to my
grave and pour this on my
headstone.
Gee, isn't this morbid?

So... 400 years should be plenty of time for him to die, right?

There's a grave here on the cape northwest of Choras. It's considered to be within the town limits, so "Tranquil Days" plays.

"Levine" rhymes with "sign", not with "scene", for what it's worth.

The party leader pours the sake on the grave, and Toma's ghost appears.

Toma: Yo, {char1}, long time no see.
I finally found the Prismatic Shell.

TOMA: {char1}, long time no see.
I've located the Rainbow Shell.

Toma: There's an island called Giant's Claw
on the seas northwest of this cape.
The Prismatic Shell is there.

TOMA: To the northwest of this cape is
a large island called the Giant's Claw.
You can find the Shell there.

The screen shows a view, in A.D. 600, panning from the cape to the northwest and stopping over an island with a small mountain on it. There's a cave in the mountain that wasn't visible until Toma pointed out the island.

Toma: But be careful.
There's hordes of monsters over there.

TOMA: But beware!
There are many beasts about!

Toma: Well, it's time I left.

TOMA: Time to shove off.

Toma's ghost rises and vanishes.

Toma: The sake I drink with you really
is the best. See ya...

TOMA: You guys are a riot a minute!
See ya!

The cave looks a lot like the Primeval caverns, and "Tyran Castle" plays too, even during battles. There's a note in the entrance.

A note Toma likely wrote is on the ground...
"The pit... what if I fall in on purpose?
 Tch... maybe I should start over..."

Anyway, the next room is where it gets interesting, because it looks just like Azarla's throne room.

Marle: Is this the Tyrano Lair?

Lucca: Is this the Tyrano Lair?

Frog: The Tyrano Lair?

Robo: THIS appears to BE
the castle of the Dinomen.

Robo: Looks like the Reptites'
castle.

Ayla: Zowah!!
Why Dinomen castle in place like this?

Ayla: What!!
Why Reptites' castle here?

Magus: A prehistoric castle?

Marle: When Lavos came falling it was
buried deep underground... and it went
on to become an ancient ruin.

Marle: This must have been pushed
underground when Lavos fell to
earth.

Lucca: When Lavos fell it was buried
deep underground, and became an
ancient ruin.

Lucca: When Lavos fell, this became
buried beneath the earth.

Frog: When Lavos came falling it was
buried deep underground... so it went
on to become an ancient ruin...?

Frog: When Lavos came hither,
this place was buried beneath the
land!

Robo: When Lavos fell, it WAS buried
underground, then stayed as it WAS
and BECAME an ancient ruin.

Robo: This must have been pushed
underground when Lavos fell to
earth.

Ayla: When Lavos rained down Tyran
Castle buried. It stay there long
long time under ground...!

Ayla: Lavos fall and Tyrano Lair
buried underground forever!

Magus: Prehistoric castle...

So this is Tyran Castle, or at least what's left of it. Many of the rooms are nearly unchanged, but most of the interconnections have been replaced with a cave system that doesn't resemble the original layout. And, of course, the monsters are tougher.

Monsters include the Fossil Ape, Ancient Saurus (Gigasaur), Ancient Nix (Leaper), and Tyran Kite (Lizardactyl). They're mostly similar to their prehistoric equivalents, with the Fossil Ape having high magical but low physical defense, and the Ancient Nix and Ancient Saurus having high physical defense until shocked but low magic defense. The Tyran Kite has normal defenses for the most part, except that in an unusual twist, it absorbs Aether damage, so simply electrocuting everything reptilian won't always work here.

There's a Power Capsule behind one of the skulls that opens by stepping on a button, and another one on the floor in the next room. In that room, there's also a half-hidden chest near the far door containing the Blue Stone, which lets the Magus, Lucca, and Robo use the very powerful Dark-based Omega Flare skill. A similar chest in the next room contains a Stardust Cape. Take the left exit from the room above the original entryway to find a chest with the Fury Bracelet. The egg in one room is still trapped to open a trapdoor to the basement, but that's fine since the basement doesn't open from the outside. Head up the stairs for yet another Power Capsule, then all the way down to find a save point. The back of the cell where Kino was held now has an opening, so head through to find... a giant T-Rex. It's a boss, with the special second boss music even.

The Rust Tyranno (Rust Tyrano) is basically a stronger version of Azarla's Black Tyranno, but at this point, it shouldn't pose much of a threat.

Regardless of its massive HP total, the Rust Tyranno has standard defenses. It sometimes chews on people to heal when it's not counting down for the fire breath, but other than that, it's rather unremarkable, especially with Fire resistance. Ayla should steal a rare Red Plate.

With the Rust Tyranno out of the way, the party continues into the cave to find a large shell that glimmers with all the colors of the rainbow.

Marle: THIS's the Rainbow Shell!

Lucca: The Rainbow Shell!

Frog: Behold!
The Rainbow Shell!

Frog isn't referring to it by the full proper name, so here's slightly different wording with no capitals. Though that may have been a simple typo.

Robo: The Rainbow Shell.

Ayla: Pretty! Big!
This Prismatic Shell?
Can eat?

Ayla: Pretty!
Big!
This Rainbow Shell?
Can eat?

Magus: Rather drab, isn't it?

So the Magus has a fashion sense. Hmm.

They try lifting it, but can't keep it off the ground for long.

Marle: Heaaaaavy!
We can't move it like this.
Let's go call in support from the castle!

Marle: It's heavy!
We won't be able to carry it.
Better get some help at the castle!

Lucca: It's too heavy.
Let's go call in support from Guardia
Castle.

Lucca: It's too heavy.
Let's get some help at Guardia Castle.

Frog: Heavy!
Let's go make a request of the king
for support from the castle.

Frog: Heavy, it be!
Let's seek the King's counsel!

Robo: It IS too heavy.
We must call in SUPPORT from
Guardia Castle.

Robo: It weighs a ton!
We must get help from Guardia
Castle.

Ayla: Heavy, heavy!
Can't move. Anybody at castle?

Ayla: Heavy heavy!
Can't carry.
Castle people help?

Magus: Who's going to carry this for
us?

The scene fades out as the party leaves...

...and fades in at the castle, saving the player the trouble of going there manually. Everyone of importance is assembled in the throne room.

By the way, there's a funny minor glitch here. Keep pressing in a direction (any direction, optionally with the run button pressed) after the screen fades out and until it fades back in at the castle. Your lead character will be stuck in the walking or running animation! The effect wears off when that character speaks, or after the scene ends, whichever comes first.

King: Good of you to come!
We welcome you at any time.
Hm? What's wrong?

KING: Hello!
You're always welcome here.
What can I do for you?

Frog: Most respectfully, we have
a request...

Robo: We would like to ask a
favor...

King: I see, you want me to take the
large shell that's on that island into
safekeeping unto future generations?

KING: I get it. You want me to keep
that huge shell safe here until the
next century, right?

Leene: The request is from none other
than {char1} and the others.
I implore you as well.

LEENE: I ask for the sake of {char1}.
Please carry out their request.

The above line looks rather odd if the Magus is your lead character, considering they were just at war! Then again, it's unlikely anyone knows him by sight.

King: Understood!
I shall have that Prismatic Shell object
moved to the castle and kept in a treasure
storehouse as an heirloom for generations.
Knight Captain!

KING: Done!
I shall obtain the shell and store it in
the castle, as a national treasure.
Knight Captain!

KNIGHT CAPTAIN: Yes, Majesty!

King: Cross to Giant's Claw and bring the huge
shell known as the Prismatic Shell back
to the castle, no matter what it takes!

KING: Go and obtain the Rainbow Shell,
and bring it back in one piece!

KNIGHT CAPTAIN: At once, Sire!

Marle: Thank you, your Majesty!
And Queen Leene too, of course!

Lucca: Thank you very much!

Frog: Thank you for doing this for
one such as myself.

Frog: Thanks to thee, from one so
humble.

Robo: Thank you very much!

Ayla: You good guy!
Ayla like!

Ayla: You, good man!
Strong!
Ayla like!

I love how she's speaking to the king without even the faintest trace of formality, and getting away with it, too.

Fortunately, the Sylbird is parked outside the castle, and not back on Giant's Claw.

As a side note, back in the bottom of the cave on Giant's Claw, the knights can now be seen diligently working to move the shell.

Soldier: H-heeeaavyyyy!
But we will not fail to transport it to the castle!

SOLDIER: It's heavy...
But we'll manage!

Knight Captain: Everyone!
Keep at it!!

KNIGHT CAPTAIN: Okay, everyone!
Lift!!!

Something's wrong. Soldiers block off most of the castle.

That's odd. What's going on? What trial? Why the chancellor's orders? Could this have something to do with what the party just did in the Middle Ages? How did the translation turn "chancellor" into "King"? Let's try asking some of the other soldiers...

Just about the only open area is the hallway to the courtroom, but soldiers guard the entrance to the trial chamber.

If Marle is in the group, she lets forth a mighty shout!

Marle: Let me through!!

The guards hastily move out of the way, and the party enters the courtroom. "Kingdom Trial" plays, and the king stands in the defendant's position, with the chancellor acting as prosecuter. There is, incidentally, no defense attorney.

Chancellor: Everyone! Do you know of the
Prismatic Shell heirloom passed
down in the royal family?
Until I saw this, I did not know of it either.

CHANCELLOR: Had any of you heard of
the "Rainbow Shell?"
I too, had no idea until I found this...

The chancellor pulls out some papers.

Chancellor: It's a will that Guardia's
distant ancestor wrote.
"Display the Prismatic Shell heirloom
to the people at the time of the National
Foundation Millennial Festival."

CHANCELLOR: It's an ancestral will.
It says, "Unveil the Rainbow Shell to
the people at the Millienal Fair."

King: I know of no such thing!
There isn't even an heirloom in this castle.

KING: What are you talking about?!
We have no family heirlooms here!

That's interesting... I thought that when the party changes history, only they (and a few special beings existing outside of normal time) are aware that things haven't always been the way they have become. So the king ought to know about the Prismatic Shell, unless it was forgotten in the past 400 years, or he somehow gained immunity to the change... or someone arranged for it to be forgotten. Or maybe it's just an oversight by the writers.

Chancellor: Are you suggesting this is a forgery?
Why does the defendant not bring the
Prismatic Shell before the people?
That is because it is no longer here.
The defendant, dazzled by greed, sold the
precious heirloom in a craving for money.
Now, the witnesses...

CHANCELLOR: So this is a forgery?
Why does the defendant deny the
people a glimpse of the "Rainbow
Shell?"
Because he no longer HAS it!!
He sold the heirloom for cash!
Witness, please!

Is that always going to be his supposed motive for everything? Maybe he's projecting...

Marle bursts into the room.

Chancellor: Wh-what is it, Princess?
We're in the middle of a trial.

CHANCELLOR: Wh, what is it, Nadia?
We are conducting a trial here.

Marle: Father!

King: Oh, Marledia, I'm about to be
framed by the chancellor!

KING: Nadia!
The Chancellor is trying to frame me!

The music fades out as the chancellor turns to address Marle.

Chancellor: How slanderous.
If there were any proof, you could
verify the king's innocence.

CHANCELLOR: He hurls insults!
Confirm your innocence with proof!

Marle: Proof?

Chancellor: Yes.
Assuming he hasn't sold the heirloom,
it should still be in this castle.
If you bring the Prismatic Shell
before my eyes, I shall admit
to the king's innocence.
Though I doubt you can... ku ku...

CHANCELLOR: Yes. If he hasn't sold the
heirloom, it should be in the castle.
Show me the "Rainbow Shell," and I'll
accept his innocence, heh, heh...

KING: Chancellor!
What kind of trickery is this?!

"Abyssal Temple" starts playing.

CHANCELLOR: Remove them!

Odd that he uses an explict plural, even though only Marle seems to have actually come all the way into the room...

A guard runs in and herds Marle out of the room. Outside, the guards resume their position blocking the door.

...but they don't actually close the door, just block the doorway. Huh?

Marle: Let me through!!

Lucca: If we bring the Prismatic Shell,
we can prove his innocence!

Lucca: Find the "Rainbow Shell,"
and we'll be able to prove the King's
innocence!

Frog: If we bring the Prismatic Shell,
we can prove his innocence!

Frog: 'Tis the "Rainbow Shell" that
shall prove his innocence.

Robo: If we bring the Prismatic Shell,
we CAN prove his innocence.

Robo: The "Rainbow Shell" will
prove the King's innocence.

Ayla: Bring Prismatic Shell!
Help Marle's father!!

Ayla: Take "Rainbow Shell!"
Save Marle's father!!

Magus: Shouldn't we just bring the
Prismatic Shell...?

Magus: Taking the "Rainbow Shell"
to them will solve this problem.

Marle: What are you saying!
That's the chancellor's made-up story.
There's no heirloom in the first place!!

Marle: What ARE you saying!?
It's a lie!
There IS no heirloom!

Lucca: Have you forgotten
what we did in A.D. 600...?
Since we changed history, the Prismatic
Shell should be here in the castle in this era!

Lucca: We changed history back in
600 A.D., so the "Rainbow Shell" should
still be in the castle!

Frog: Have you forgotten
what we did in A.D. 600?
Since we changed history, the Prismatic
Shell should be here in the castle in this era.

Frog: Hast thou forgotten?
History hath been changed, and the
shell is within the castle.

Robo: HAVE you forgotten
what we did in A.D. 600?
Since we changed history, the Prismatic
Shell should BE here in the castle in this era.

Robo: We altered history in 600 A.D.!
The "Rainbow Shell" should be here
in the castle.

Ayla: Remember, Marle!
Aylas asked old times king!
Prismatic Shell now here in castle!
That wrong?

Ayla: Remember Marle?!
We ask old king save shell!
"Rainbow Shell" here now!

Magus: Idiot, you forgot
what we did in A.D. 600...?

Magus: Idiot!
Have you forgotten our trip to 600
A.D.?

Marle: I get it!
You're saying the Prismatic Shell we
left with the King in A.D.600... meaning
my ancestor, is stored here even now
after 400 years have passed, right?

Marle: Aha!
The "Rainbow Shell" we gave to my
ancestor 400 years ago is still here.

Marle: Let's go.
It's got to be in the basement!

Marle: It's probably in the
basement!

Downstairs, there's another stairwell going down that wasn't there before asking the king of A.D. 600 to store the Prismatic Shell. The guard at the bottom of the stairs is lying on the ground...

Well. Anyway, there are two Biters (Gnashers), the weak snake monsters from Manoria Abbey early in the game, just around the corner.

Slitherta: It's so great that the boss will be
able to avenge the 13-generation grudge.
Kee, kee, kee, kee!

DUMB: The boss is itching to avenge the
grudge that's been in the family for
13 generations!
Gee hee!

にょろにょろ (nyoronyoro) represents the sound of a slithering snake. I'm not sure what, if anything, the ending た (ta) here and ぽん (pon) in the next line mean, so I just tacked them onto "slither".

Slitherpon: He says the king'll be put
to death from the made-up evidence.
Kee, kee, kee, kee!

DUMBER: He's gonna frame the king!
Ga haw!

Then they notice the party and attack. The music keeps playing even during battle. But the monsters are as weak as ever, so no worries.

Marle: There really is a conspiracy!
Let's hurry!

Marle: So there IS a plot!
Let's hurry!

The scene jumps back to the courtroom. A generic man is testifying.

Merchant: Yes, I definitely bought
it from his majesty. He seemed
to be hard up for cash, and...

MERCHANT: I confess.
I bought it from the king.
He said he needed the cash.

King Guardia: Don't lie!
I've never even met you.

KING: Liar!!
I've never even seen you before!

The merchant walks up close to the chancellor.

Merchant: Heh, heh.
Was that good?

MERCHANT: Heh heh.
Was I convincing?

The scene jumps back to our heroes, who are abruptly attacked by more monsters, including a Mianne (Naga-ette), but winning is effortless. The are more weak monsters down the hallway, several setting up pointless ambushes. At the far end, sitting in an elevated carpeted alcove, is the Prismatic Shell. Marle must be in the active group to do anything with it. The music fades out as she approaches the shell.

Marle: The Rainbow Shell!!

Lucca: What's this...a letter?

Robo: There is a letter?

Frog: Why, 'tis a letter?

Ayla: Something here!
Paper here, paper here!

Ayla: Something here!
Paper here, paper!

Magus: There's a letter.
Burn it?

Magus: There's a letter here.
Shall we burn it?

Marle: To Marle...?
Dear Marle.
How are your relations with your father?
At present, you may not understand,
but though you may quarrel or be distant,
parent and child are parent and child.
You must someday leave your parent's nest.
Then you too will someday become a parent.
That will not change in any generation.
That exactly is why we and you are also linked...
From Leene, queen to King Guardia XXI.

Marle: To Marle...?
"Dearest Marle, I know things
are tough between you and your
father.
But nothing can break your bond of
blood. Neither words of anger, nor
great distances.
Someday, when you have children,
you will understand.
This special bond is part of a family
tree which links us together.
 -Queen Guardia XXI, Leene."

Lucca: What a horribly wonderful thing to do...
Wait, this is no time for that!

Lucca: Boy, can she tell it like it is!!

Frog: Lady Leene...
Come on, let's hurry on!

Frog: Dear Queen Leene...!
Let us now make haste and fulfill our
quest!

Robo: I have no parents, so I do NOT
understand the feeling of loving a child,
but this text IS somehow... warm.

Robo: Although I have no emotions,
there is something warm and cozy
about this letter.

No emotions? Really?

Ayla: Oh, leave nest!
Ayla understand that too!
Pteran leave nest too.
Time pass, leave nest!
Marle leave nest too?
That great!

Ayla: Ayla know about
leaving nest!
Time pass, grow big, leave nest!
Ayla leave nest!
Dactyl leave nest too.
Marle leave too?
Big change!

Ayla: Leave nest! Make baby!
Bear kids! Give boobs!
Then kids leave nest again!

Ayla: Leave nest!
Have baby!
Baby grow big!
Leave nest too!

おっぱいやる (oppai yaru) is literally a crude term for "breasts" plus a verb meaning "do" or "give". Of course she means nursing, but she doesn't say it very politely.

Magus: I don't think this is any time
to be getting all emotional...

Magus: Perhaps we could have this
conversation later...?

Marle: Father!
Hang in there, we're coming!

Marle reaches for the shell.

Ayla: You be okay?
No have boobs...

Ayla: Sure you ready leave nest?
Not too big yet.

Marle crosses her arms across her chest.

I have to admire Ayla's ability to be totally open and honest about anything and everything. Though to be fair, it's clear from the concept art that Marle does have breasts, but of a modest size (unlike Ayla and many other anime females), and her clothing is fairly baggy as well. Anyway, it seems that Ayla is concerned that Marle may have trouble nursing the kids, and it doesn't occur to her that saying this could be considered embarrasing or insulting. On the other hand, おっぱい could also refer to breast milk rather than the breasts themselves, but Ayla would know that women don't constantly lactate. Wouldn't she?

The scene shifts back to the courtroom again. "Concealed Truth" plays.

Presiding Judge: Jurors.
Go, those who think he is guilty to the left,
those who think he is not guilty to the right!

JUDGE: Members of the jury...
If he is guilty, stand to the left.
If innocent, stand to the right.

The first juror enters.

He moves to the left as the next juror enters. The scene switches back to the party, still in the basement. The music keeps playing even if they get into battles on the way out. Back upstairs, the guards are still refusing entrance to the courtroom. Marle must be in the active group to proceed.

Marle: You won't reconsider?

SOLDIER: No, Princess.

Marle: There is a way!
It's a bit rough, though...
Follow me!

Marle: There is one way...
It's a bit rough, but just follow me!

The music comes to a conclusion. Marle and the others run down the hall, and the scene moves back into the courtroom.

Presiding Judge: I now announce the verdict!
4 guilty, 1 innocent.
Accordingly, we find him guilty!!

JUDGE: The verdict is in!
Guilty!!!

Someone give that lone juror a medal. The others can have a gullibility test, or perhaps a corruption investigation.

Chancellor: And now, the age of
Guardia has ended...
From now on, I will run the country.
Now! Take him away!!

CHANCELLOR: The Guardia line ends
here.
This domain shall be mine!
Take him away!

Wait. With the king removed, the chancellor takes over? And he was the prosecutor? Wow, can you say "conflict of interest" and "system is broken"?

Wait!!!

CHANCELLOR: Who is it?!

"Manoria Abbey" starts playing, and Marle's silhouette appears behind the massive stained-glass window in the back of the courtroom, which depicts the figure of a wise-looking old man with a large set of scales, presumably symbolic of the justice system. Marle roams around as though looking for something, climbs something up to about the top of the figure...

Marle: FATHER!!!

...crashes through from behind, shattering the figure's head and chest, which is probably symbolic of something, and lands in the middle of the courtroom. The jurors all rush out of the room, and the chancellor looks shocked.

KING: Nadia!

Chancellor: Lady Marledia!

CHANCELLOR: Princess!
Control yourself!

Chancellor: H-however, you are too late!
King Guardia's sentence was decided
in a trial by the people. King or not...

CHANCELLOR: You're too late!
The King has been found guilty.
Even kings are subject to our laws.

Marle: Not a chance!
You framed him!!

Marle: No, this was a set up!

Chancellor: Oh no, the truth about the
king is, the royal family's treasure...

CHANCELLOR: Nonsense!
The King's a crook!

Marle: But the treasure is right
here!

Marle opens the doors to let in the other two (I thought they were following her?), and holds out the shard.

CHANCELLOR: IMPOSSIBLE!!

Marle: Your little scheme is over,
Chancellor!

CHANCELLOR: Grrr...I mean...uh...

Marle: Huh?

Chancellor: Ku ku ku ku...
You're the ones who should give it up.
I'll be paying back the grudge inherited
from my ancestors, here and now!

CHANCELLOR: Hee hee hee!
It's not the plot you think!
I'm here to avenge my ancestors!

The king rushes out of the room, and the judge just sort of disappears. The music fades out as the chancellor moves to the middle of an open area.

Chancellor: Super Ultra Deluxe
Chancellor CHANGE!!

CHANCELLOR: Super, ultra, presto...
TRANSFORM-O!!!!!!

And with cheap special effects, he turns into an ugly blue-grey Yakra-looking thing. Remember, the boss near the beginning of the game that took the place of the chancellor in A.D. 600? That Yakra. Anyway, it's time for a boss battle. He's been asking for a beating ever since Crono's trial anyway.

Yakra XIII has standard defenses and a fairly high HP total. He uses an annoying confusion-inducing attack, but other than that can't do much for the first stage of the battle. Equip gear that prevents confusion for best results. After a while, he starts talking...

After reaching the last line, he unleashes a fairly powerful attack against one character. After this point, he will fairly often yell:

...and use the same attack. He'll also occasionally use a similar attack that hits everyone at once. Keep health up, and he'll go down. Ayla can steal both a Last Elixir and a rare White Plate from Yakra XIII. When his HP runs out...

...he uses the needle attack that hits everyone, one last time. If a counterattack finished him off, he falls without getting to use the final attack.

A shiny something lands on the ground where he died, King Guardia comes back into the room, and "At the Bottom of Night" begins to play.

Marle: Father...
I...

Marle: Father...
I...

King: It's all right. Don't say a thing.
I shouldn't have been so obstinate.

KING: No, don't say it.
I was wrong to be so stubborn.

Marle: I'm the one who didn't even
understand your feelings...
No...
I got it in my head, but I couldn't
put it into words very well...

Marle: No, I didn't even think about
how you felt.
Um...
I know it in my heart, but the words
just come out wrong.

King: Nor could I.
For a time, it seemed as though
you had truly gone far away.
But upon thinking it over well,
the one who had gone far was I.

KING: I too, have that problem.
I thought you left me, but realized
that it was I, who abandoned you.

Marle shakes her head.

Marle: Now we're close.
From now on, I can tell you anything.
Seek advice on things,
talk about Crono,
ask about mother...

Marle: But I'm here now.
We'll talk about everything that's
happened.
About Crono, and mother, and...

King: Your mother... I'm embarrased to say
so, but I feel like I've only now finally come
to understand her words on that day.
The words Ariche said before she
breathed her last...
"When Marledia grows up, the day
is bound to come when she brings
the person she loves before you.
When that happens, welcome the
two of them warmly.
...that day will, after all, be a wonderful,
unforgettable day for you as well."

KING: Your mother...
How sad! It has taken me so long to
understand what Aliza meant with
her last words.
"Someday when Nadia grows up,
she will bring her beloved to meet
you.
Welcome him warmly.
It will be a day you remember
forever."

"Ariche" is the best I can do with アリーチェ (ARIICHE). That's a long i, and the ending is like "Chex" (the cereal) minus the 'x'.

Marle: So, you were listening to
mother's last words, then?

Marle: You...heard her last words?

King: Yes...
You were little so you may
not remember, but...
You were frolicking about, saying,
"Daddy, there's lots of people
I love! Lots and lots!"
Seeing you like that, Ariche
was at peace and smiled as
she breathed her last...

KING: Of course!
You were so young!
You ran around saying "Daddy, it's
fun having all my favorite people
here!"
Seeing you so happy, she felt
reassured, and she left us quite
peacefully.

Marle: So that's how it was...

KING: Yes, why?

Marle stands there for a few moments, as if thinking about something, before turning to continue the conversation.

Marle: When I was little,
I called you daddy.

Marle: I used to call you "Daddy?"

KING: You did.

Marle walks over and hugs him.

Marle: I'm sorry...
Daddy...
I'm really sorry for saying selfish things...

Marle: I'm sorry...Daddy.
I'm really sorry for doubting you.

The scene moves to the throne room, where King Guardia sits on the throne and "Courage and Pride" plays.

King: I will accept your leaving the castle.
However! I insist that you be careful.
All of you, take care of my daughter.

KING: I'll let you exit the castle, BUT!
...you be careful, now.
Take care of her!

Crono nods.

Ayla: You worrywart!
Ayla protect Marle!

Ayla: You no worry!
Ayla protect Marle!

The Magus makes no response.

The doors open, and Marle and the others turn to see Bosch walk into the throne room.

Bosch: As if I'd let you guys
take all the tasty parts.
I'll handle making armor from
the Prismatic Shell!
My first turn in quite a long time.
I'm itching for action!

MELCHIOR: Can't let you run the whole
show. Let me make some weapons
from the Rainbow Shell!
Finally time for me to do somethin'.
Watch and learn!

He walks back out of the throne room. Meanwhile, the king's new line is:

Remember the shiny thing Yakra XIII dropped? Let's go check that out. "Kingdom Trial" still plays in the courtroom.

And the stained glass is miraculously repaired...! The spectators apparently have nothing better to do than sit around here, either.

There's a locked chest partway down the stairs that this key opens. The chest opens, and the real chancellor pops out!

Chancellor: Phew, I'm saved!
That damn monster, shutting
me up in a place like this...!

CHANCELLOR: Phew, finally!
That beast, keepin' me locked up in
here...!

Chancellor: Oh, lady Marledia!
These are your friends?

CHANCELLOR: Princess Nadia!
Your friends, I presume?

Suddenly, his jaw drops open.

Chancellor: Oh, this simply won't do.
I have to set about preparing for the
Millennial Festival Moonlight Parade!

CHANCELLOR: Wait, I don't have time for
this.
I must prepare for the Moonlight
Parade!

Bosch awaits the party in the basement by the Prismatic Shell.

Bosch: This is a remarkable material.
Armors made of this will be able to dampen
the effect when you suffer magical attacks.
A Prism Dress would be very effective,
but I couldn't make more than one.
Prism Helms would be less effective,
but I could make three of them.
Which will you choose?

MELCHIOR: This is a very rare!
As armor, it deflects magic!
I can make you 1 Prism Dress,
featuring maximum defense.
Or I can make 3 less-effective
Prism Helms.
Which would you prefer?

After the player picks one, Bosch gives more information and a chance to switch choices.

Bosch: The Prism Dress?
Only the girls can equip that one.

MELCHIOR: The Prism Dress?
Only females may equip it.

Bosch: The Prism Helms?
Anyone can equip those.

MELCHIOR: You want Prism Helms?
You're sure?

Bosch: Okay, just you wait!
Applying my skill to its utmost, I, Bosch,
shall forge once-in-a-lifetime goods!

MELCHIOR: All right, you just wait there!

The screen fades out, there are noises as of a busy construction site, and then the scene fades back in.

Bosch: It's done.
Take this with you!

MELCHIOR: Finished!
Off you go, now!

This is a difficult decision to make, since both choices are so good. I generally choose the helmets because I can outfit the whole active party with them, and they also prevent status effects. Refer to the items page for details.

There's also a way to get three more of each in addition to whatever you get here. Refer to the Black Dream sidequest for information on that.

Bosch stays around after making the armor, but that's it for this sidequest. Rewards: 3 Power Capsules, Blue Stone, Stardust Cape, Fury Bracelet, White Plate (steal), a choice of 1 Prism Dress or 3 Prism Helms, and various other treasures. Also, there are additional rewards for completing both this sidequest and the Solar Stone sidequest (in either order).

On a side note, the dining hall now serves food upon request, and one of the options is called the...

Order it for an interesting remark.

Finding the Prismatic Shell and having it stored in Guardia Castle had an obvious historical impact. It also led the false chancellor to show his hand in a situation where Marle and the others were able to foil him for good, when he might otherwise have kept manipulating events from behind the scenes indefinitely—the locked chest was there all along, not to mention the various suspicious things the phony had been doing, so he had already taken the real chancellor's place before history was changed. Getting Marle and King Guardia to reconcile also has potential implications for the future.