Roedd hi'n noson oer ym Medi pan benderfynodd Bethan dreulio diwrnod yn crwydro o amgylch Castell Conwy, adeilad mawreddog sy'n codi uwchben y dref hanesyddol.

It was a cold night in September when Bethan decided to spend a day wandering around Conwy Castle, a majestic building that rises above the historic town.

Gyda'i waliau trwchus a'i thyrau uchel, roedd y castell yn swyno Bethan gyda'i hanes a'i storiâu.

With its thick walls and tall towers, the castle captivated Bethan with its history and stories.

Eto, wrth i'r haul ddechrau gostwng tu ôl i gopaon yr wybren, doedd Bethan ddim yn sylwi fod ymwelwyr eraill y castell yn dechrau gadael.

Yet, as the sun began to descend behind the tops of the trees, Bethan didn't notice that the other visitors to the castle were starting to leave.

Yn awyddus i archwilio mwy, aeth hi i edrych ar oriel o hen bortreadau a darllen am dywysogion a brenhinoedd a fu'n byw yno gynt.

Eager to explore more, she went to look at a gallery of old portraits and read about princes and kings who had once lived there.

Collodd hi ym myd y gorffennol, nes iddi sylweddoli bod gweddill y castell tawel iawn.

She lost herself in the world of the past, until she realized that the rest of the castle was very quiet.

Cerddodd trwy'r ystafelloedd wag a'r coridorau distaw, galwodd am help, ond doedd dim ymateb.

She walked through the empty rooms and quiet corridors, calling for help, but there was no response.

Roedd hi wedi'i chloi y tu mewn i Gastell Conwy ar ôl i'r dydd ddirwyn i ben.

She found herself locked inside Conwy Castle after the day had come to an end.

Wrth i'r noson dywyllu, dechreuodd Bethan deimlo'n bryderus.

As night fell, Bethan began to feel anxious.

Goleuni'r lleuad yn pasio trwy ffenestri uchel y castell a daeth y cysgodion yn fyw.

The moonlight passed through the high windows of the castle and the shadows came alive.

Tra'n eistedd ar y grisiau carreg, penderfynodd Bethan aros tan y bore cyn chwilio am ffordd allan eto.

Sitting on the stone steps, Bethan decided to wait until morning to look for a way out again.

Ond yna, aeth hi'n sylweddol o bresenoldeb rhywbeth arall - sŵn traed yn cilio'n y coridorau, chwerthin distaw ond byw.

But then, she realized the presence of something else - the sound of footsteps echoing through the corridors, quiet but lively laughter.

Cyn hir, daeth wyneb disglair, heini i'w golwg.

Before long, a bright face appeared, piercing her gaze.

Ysbryd oedd yma, efo gwen chwareus ar ei wyneb.

There was a spirit here, with a playful smile on its face.

Dywedodd ysbryd ei fod yn enwog am ei ddrwgdeimlad, ac enw'r ysbryd oedd Rhodri.

The spirit said it was famous for its mischievous nature, and the spirit's name was Rhodri.

Er ei syndod, doedd Rhodri ddim yn peri ofn iddi, ond yn hytrach deimlad o gysur a hiwmor.

To her surprise, Rhodri did not cause her fear, but rather a feeling of comfort and humor.

Fe wnaethon nhw dreulio'r nos yn sgwrsio, gyda Rhodri'n adrodd straeon am oesau a fu a Bethan yn gwrando'n eiddgar.

They spent the night chatting, with Rhodri recounting stories of ages past, and Bethan listening eagerly.

Wrth i'r oriau fynd heibio, daeth hi'n ffrindiau gyda'r ysbryd drwgdeimlad.

As the hours passed, she became friends with the mischievous spirit.

Wrth i'r wawr ddechrau torri, datrysodd Rhodri'r ddirgelwch am sut i ddianc o’r castell.

As dawn began to break, Rhodri solved the mystery of how to escape from the castle.

Roedd ganddo wybodaeth am gyfrinachau'r castell nad oedd neb arall yn gwybod amdanynt - gan gynnwys llwybr cuddiedig oedd yn arwain allan o’r castell.

He had knowledge of the castle's secrets that no one else knew - including a hidden path leading out of the castle.

Wedi dysgu am y llwybr hwnnw oddi wrth Rhodri, fe wnaeth Bethan ei dilyn a dod o hyd i fynedfa ddirgel.

After learning about the path from Rhodri, Bethan followed it and found a secret exit.

Roedd hi rŵan yn safio tu allan i furiau castell, wrth i oleuni'r bore ledaenu dros y dref.

She was now standing outside the castle walls, with the morning light spreading across the town.

Roedd hi'n ddiwrnod newydd ac roedd Bethan yn teimlo'n llawn diolchgarwch tuag at ei ffrind ysbrydol newydd, Rhodri.

It was a new day, and Bethan felt grateful to her new spirit friend, Rhodri.

Cyn iddi adael, trodd i edrych yn ôl ar y castell a gweld Rhodri'n chwifio ffarwel.

Before she left, she turned to look back at the castle and saw Rhodri waving goodbye.

Ag ef, roedd Bethan wedi dysgu gwers bwysig: weithiau, mewn lleoedd mwyaf annisgwyl, gallwn ddod o hyd i ffrindiau a chyfleoedd i ddysgu a thyfu.

With him, Bethan had learned an important lesson: sometimes, in the most unexpected places, we can find friends and opportunities to learn and grow.

Ac felly, gyda chalon lawn a phendantrwydd, aeth Bethan yn ôl i'w bywyd bob dydd, byth i anghofio ei hail noson yn Castell Conwy.

And so, with a full heart and determination, Bethan returned to her everyday life, never forgetting her night at Conwy Castle.