Ym mynyddoedd Gwynedd, roedd castell hynafol yn sefyll, ac roedd Rhys, Carys, ac Eira yn ymweld ag ef ar ddiwrnod poeth o'r haf.

In the mountains of Gwynedd, an ancient castle stood, and Rhys, Carys, and Eira visited it on a hot summer day.

Roedd muriau'r castell wedi'u gorchuddio ag eiddew a chyfrinachau llawer cyhyd.

The castle walls were covered in ivy and many secrets long hidden.

Roedd Rhys bob amser yn chwilfrydig, Carys yn feddylgar a rational, ac Eira yn anturus.

Rhys was always curious, Carys thoughtful and rational, and Eira adventurous.

Ar y prynhawn hwnnw, daethant at y llyfrgell drist gyda llyfrau lledr llwchog.

That afternoon, they came across the forlorn library with dusty leather books.

Yn y gornel, gwnaeth Rhys ddarganfod dyddiadur dirgel.

In the corner, Rhys discovered a mysterious diary.

Roedd y dyddiadur yn hynafol, a'r ysgrifen arno'n anodd ei deall.

The diary was ancient, and the writing on it was hard to decipher.

"Gawn ni weld," meddai Rhys, gan dendio'r llyfr agored.

"Let's see," said Rhys, tending to the open book.

"Mae rhywbeth yma, rwy'n siwr.

"There's something here, I'm sure."

"Roedd Carys yn ansicr.

Carys was uncertain.

"Efallai na ddylwn ni ddarllen hyn.

"Maybe we shouldn't read this.

Dydyn ni ddim yn gwybod beth yw e.

We don't know what it is."

"Roedd Eira yn bendant wrth feddwl.

Eira was resolute in her thinking.

"Rhaid i ni archwilio mwy o'r castell," meddai hi, gyda llygaid yn disgleirio o gyffro.

"We must explore more of the castle," she said, her eyes gleaming with excitement.

Wrth iddynt edrych ar y dyddiadur, clywodd y tri swn traed.

As they looked at the diary, the three heard the sound of footsteps.

Roedd teimlad o gael eu gwylio yn llechu.

There was a feeling of being watched lurking.

"Mae'n rhaid i ni gael help i ddehongli'r ysgrifen," meddai Rhys, gan ystyried gyda phwyll.

"We must get help interpreting the writing," said Rhys, considering prudently.

Roedd Carys yn cynnig, "Rydyn ni'n well i adael nawr.

Carys suggested, "We’d better leave now.

Dydy hyn ddim yn teimlo'n iawn.

This doesn’t feel right."

"Ond roedd Eira'n brwdfrydig.

But Eira was enthused.

"Let’s fynd i archwilio yn fwy,” meddai'n wrth-ddiddigrwydd.

"Let's go explore more," she said with determination.

Roedd y penderfyniad wedi'i wneud.

The decision was made.

Aethant o'r llyfrgell i mewn i do arall o'r castell.

They left the library and entered another wing of the castle.

Yna, derbyniodd Rhys syniad i edrych o dan garreg wledd.

Then, Rhys got the idea to look under a banquet stone.

Yn sydyn, roedd siambr gudd yn agor.

Suddenly, a hidden chamber opened.

Roedd y nifer o hen drysorau gerbron eu llygaid.

Numerous ancient treasures lay before their eyes.

Ond roedd mwy i hyn na dim ond aur a gemau.

But there was more to it than just gold and jewels.

Pan ddarllenodd Rhys y llyfrau yn y siambr, deallodd pwrpas y dyddiadur dirgel.

When Rhys read the books in the chamber, he understood the purpose of the mysterious diary.

Roedd y cyfrinachau wedi'u cadw yma ers cenedlaethau.

The secrets had been kept here for generations.

Rhywbeth yn frawychus iawn ydoedd.

It was something very frightening.

Roedd Rhys yn edrych o amgylch, yn cael fwy o barch at hanes a'r dirgel fel erioed.

Rhys looked around, gaining new respect for history and mystery like never before.

Roedd Carys yn teimlo bod angen derbyn mwy o antur.

Carys felt the need for more adventure.

Roedd Eira, er hynny, wedi dysgu na allai esgeuluso pryderon.

Eira, however, had learned she couldn't neglect concerns.

Ar ddiwedd y dydd, roedden nhw wedi darganfod nid yn unig trysorau pendant, ond hefyd y wers fod pob cyfrinach wedi'i rhoi yn ei le gyda chysoni.

By the end of the day, they had not only discovered tangible treasures but also the lesson that every secret is placed with a purpose.

Roedd hyn i gyd yn profi bod, weithiau, mae'r gorffennol yn dychrynllyd yn ogystal a phrydferth.

This all proved that sometimes, the past is both terrifying and beautiful.

Wrth adael y castell, roedd y tri yn dawel a diolchgar.

As they left the castle, the three were silent and thankful.

Roeddent yn gwybod yr holl ddathliadau a pheryglon cyfrinach heddiw.

They knew all the celebrations and dangers of secrecy today.

Roedd gan Rhys barch newydd at y gorffennol a’r dirgel.

Rhys had a newfound respect for the past and the mysterious.

Roedd Carys yn barod am fwy o antur, ac wrth gwrs, roedd mwy o bwyll gan Eira.

Carys was ready for more adventure, and of course, Eira had gained more prudence.

A hefyd, nid o reidrwydd roedd pob cyfrinach i’w datgelu.

And also, not every secret needs to be unveiled.