Roedd hi'n noson oer a sêr yn disgleirio yn y wybren pan benderfynodd Megan a'i ffrindiau Dylan a Gareth fynd ar antur i Gastell Caerffili.

It was a cold night with stars shining brightly in the sky when Megan and her friends, Dylan and Gareth, decided to go on an adventure to Caerphilly Castle.

Roedd y castell yn edrych yn drawiadol gyda'i furiau cerrig mawr a'i dyrau uchel yn codi tuag at y nefoedd.

The castle looked majestic with its large stone walls and towering gates reaching up towards the heavens.

"Edrych!

"Look!

Mae hi'n hwyr," meddai Gareth, yn tynnu ei oriawr o'i boced.

It's getting late," Gareth said, pulling his watch from his pocket.

"Mae'n amser i ni fynd adre.

"It's time for us to go home."

"Ond roedd Megan yn chwilfrydig.

But Megan was curious.

"Beth am grwydro ychydig mwy?

"What about wandering a little more?

Efallai y darganfwn rywbeth cyfrin," meddai hi, gan dynnu flashlight o'i bag.

Maybe we'll discover a secret," she said, pulling a flashlight from her bag.

Dylan, sy'n ofni'r tywyllwch, oedd y cyntaf i anghytuno.

Dylan, who was afraid of the darkness, was the first to disagree.

"Megan, mae'n beryglus.

"Megan, it's dangerous.

A beth os câi ni ein cloi i mewn?

What if we get locked inside?"

"Megan chwerthin.

Megan laughed.

"Peidiwch â bod mor afresymol," meddai.

"Don't be so silly," she said.

"Dim ond edrych o gwmpas am funud.

"Just look around for a minute."

"Wedi eu perswadio, dilynodd Dylan a Gareth Megan i mewn i'r neuaddau tywyll.

After persuading them, Dylan and Gareth followed Megan into the dark halls.

Roedd murmur yr awel o amgylch y wal yn creu synau rhyfedd.

The murmur of the wind around the walls created strange sounds.

Wrth iddynt grwydro tu mewn, sylwodd Megan fod y drws ar y tu ôl iddynt wedi cau.

As they wandered inside, Megan noticed that the door behind them had closed.

Gyda phwysau calon, gafaelodd hi yn ei flashlight.

With a pounding heart, she gripped her flashlight.

Yn annisgwyl, clywodd sŵn clo yn cwympo i mewn i'r latch.

Unexpectedly, they heard a door closing from inside the castle.

"Caeedig?

"Locked?"

" Dylan ei lais yn crynu.

Dylan's voice trembled.

Doedd dim signal ffôn, dim golau heblaw am y flashlight bach yn Megan ei llaw.

There was no phone signal, no light except for Megan's small flashlight in her hand.

Roedd y teimlad o bryder yn dechrau lledaenu trwy'r tri ohonynt.

The feeling of worry began to spread through all three of them.

"Mae'n rhaid i ni ddod o hyd i ffordd allan," meddai Gareth, ei lais yn llawer mwy dewr nag oedd ei galon.

"We need to find a way out," Gareth said, his voice much braver than his heart.

Gan ddefnyddio'r flashlight, aethant trwy'r coridorau carreg, y grisiau cul, a'r ystafelloedd gwag, gan chwilio am allanfa.

Using the flashlight, they went through the stone corridors, narrow stairs, and empty rooms, searching for an exit.

Sŵn eu camre yn ecoio yn y tawelwch.

The sound of their footsteps echoed in the silence.

Ar ôl oriau o chwilio, roedd ei traed yn blino a'i gwefusau yn ysgwyd o'r oerni.

After hours of searching, their feet were tired and their lips shivering from the cold.

Ond gyda phob cam, roedd Megan yn dod yn fwy penodol.

But with every step, Megan became more determined.

"Ni fydd hyn yn ein gorchfygu," meddai hi, â chryfder yn ei llais.

"This won't defeat us," she said, with strength in her voice.

Yn sydyn, yn un o'r ystafelloedd hanesyddol, gwelodd Gareth gysgodion synnu.

Suddenly, in one of the historical rooms, Gareth noticed surprising shadows.

"Edrychwch!

"Look!"

" ebychodd.

he exclaimed.

Roedd achos wedi darganfod drws cudd.

The group had found a hidden door.

Gyda phwysau aruthrol, gwthiodd arno.

With tremendous pressure, he pushed it open.

Agorodd â sgrechian ysgafnach nag unrhyw sŵn arall o'r noson honno.

It creaked open with a lighter scream than any other sound of that night.

Hon oedd yr allanfa.

This was the way out.

Y tri ffrindiau yn chwysu o ryddhad wrth gamu i'r awyr nos ffres.

The three friends sighed with relief as they stepped into the fresh night air.

Roedd y castell yn sefyll tawel a balch yn y cefndir, fel pe bai'n gwenu am eu hacen ddiweddaraf.

The castle stood quiet and proud in the background, as if it was smiling at their most recent adventure.

Yanglodd Megan y flashlight i lawr gyda chwerthin llawn rhyddhad.

Megan pointed the flashlight downwards with a laugh of relief.

"Fe berfformiodd dy flashlight yn wych," meddai Dylan, ei lygaid yn disgleirio o ddiolchgarwch.

"Your flashlight performed wonderfully," Dylan said, his eyes shining with gratitude.

Wrth iddynt gerdded yn ôl tua'r dref, penderfynodd Megan, Dylan a Gareth adael eu hanturiaethau i'r dydd.

As they walked back towards the town, Megan, Dylan, and Gareth decided to leave their adventures for the day.

O hyn ymlaen, byddai ymweliadau â chastell yn digwydd cyn bod y haul yn machlud.

From now on, castle visits would happen before the sun set.

A dyna sut y daeth Megan a'i ffrindiau i ddatrys dirgelwch y castell yn ystod noson o antur a chyfeillgarwch.

And that's how Megan and her friends solved the mystery of the castle during a night of adventure and camaraderie.

Ac roedd yr hanes yn fyw ymhob stryd a chornel o Gaerffili am flynyddoedd i ddod.

And the story lived on in every street and corner of Caerphilly for years to come.