Mae'r awyrgylch yn Ysgol Gynradd Gilfach Goch yn llawn cyffro.

The atmosphere at Ysgol Gynradd Gilfach Goch is full of excitement.

Mae disgyblion yn sibrwd am y daith maes sydd i ddod.

The students are whispering about the upcoming field trip.

Mae'n Hydref, ac mae awyr y wlad yn glir, ond mae cymylau tywyll yn mân ar y gorwel.

It's October, and the country sky is clear, but dark clouds are faint on the horizon.

Mae Gareth yn sefyll ar ei ben ei hun, wrth fyrddio'r bws.

Gareth stands alone as he boards the bus.

Mae ei linell gellyg o fflach oedd ar ei freichiau, felly mae'n cyffwrdd â'i freichiau, ond mae'n llygaid yn frwdfrydig.

His coat of pearly flashes was on his arms, so he touches his arms, but his eyes are enthusiastic.

"Ydych chi'n barod, Gareth?

"Are you ready, Gareth?"

" gofynnodd Rhian, oedd yn sefyll gerllaw.

asked Rhian, who was standing nearby.

"Ydw," atebodd Gareth yn dawel, cyn troi i lawr i edrych ar ei esgidiau.

"I am," Gareth answered quietly, before turning down to look at his shoes.

Roedd ei feddwl wedi'i hameilio ar stori newydd am fytholiaeth yr Wyddfa.

His mind was anchored on a new story about the mythology of yr Wyddfa.

Aeth y bws ymlaen, a chawsant eu cymryd i dir y bryniau enfawr, gyda'r coed yn llawn dail aur ac amber o'u cwmpas.

The bus moved on, and they were taken to the land of the massive hills, with trees full of golden and amber leaves surrounding them.

Roedd teimlad o dirgelwch yn yr awyr, fel pe bai eu taith yn mynd i ddatgelu cyfrinachau cuddiedig y mynyddoedd.

There was a feeling of mystery in the air, as if their journey was going to reveal the hidden secrets of the mountains.

Unwaith y cawsant eu hiedi i'r maes parcio, fe greodd y tywydd yn gyflym.

Once they were led to the parking area, the weather quickly changed.

Fe chrwydrodd glaw mân ar y llethrau.

Fine rain roamed the slopes.

Dyma'r adeg y gwelodd Gareth gyfle prin: mynediad i lwybr llai adnabyddus a gydnabyddwyd gan ychydig wylwyr yn unig.

This was the moment Gareth saw a rare opportunity: access to a lesser-known path recognized by few watchers.

"Peidiwch â symud i ffwrdd ormod," rhybuddiodd athro.

"Don't wander off too far," warned a teacher.

Ond roedd Gareth yn teimlo tyniad.

But Gareth felt a tug.

Synisiodd am funud, ond roedd y rhuo hwnnw yn ei galon yn ei wthio ymlaen.

He hesitated for a moment, but that roaring in his heart pushed him forward.

Fe ddechreuodd gamu'n ofalus ar hyd y llwybr ceudwllus.

He began to step carefully along the winding path.

Roedd ei galon yn curo'n gyflym wrth iddo graffu oddi ar gwmpas ei draed.

His heart was beating quickly as he looked around his feet.

Yn fuan ar ol, roedd y glaw yn trymhau, ond dal i symud ymlaen a wnaeth Gareth nes iddo ffeindio disaith dinod bach o flaen ogof cel.

Soon after, the rain intensified, but Gareth continued to move forward until he found a small, inconspicuous clearing in front of a hidden cave.

Roedd ogof Rhigolig, y lle a sônwyd yn y chwedlau.

It was Ogof Rhigolig, the place mentioned in the legends.

Teimlodd lychio yn ei asgwrn cefn wrth iddo caramu am adeg.

A shiver ran down his spine as he paused for a moment.

"I fynd mewn neu i beidio?

"To go in or not to go?"

" meddyliai, gan deimlo'r ŵr a'r danlota o gyffro.

he thought, feeling the warmth and tingle of excitement.

Yna gwnaeth Gareth penderfyniad.

Then Gareth made a decision.

Mentrodd i mewn, am funud yn unig, nes iddo weld golwg eithriadol: cerrig ar ffurf rhyfeddol, yn union fel un o'r arteffactau yn llyfrau'r chwedlau.

He ventured inside, if only for a moment, until he saw an extraordinary sight: stones in a strange formation, just like one of the artifacts in the books of legends.

Cyrhaeddodd y cwmwl glas llwybr.

The gray cloud reached the path.

Roedd y glaw mor drwm na chawnist wylio heb hysbyseb, ond Gareth ar frys.

The rain was so heavy that one couldn't watch without a visor, but Gareth hurried.

Pan ddychwelodd i'r grŵp, roedd ei ddillad yn wlyb drwy'r arferiad, ond roedd golwg o foddhad ar ei wyneb.

When he returned to the group, his clothes were soaked as expected, but there was a look of contentment on his face.

Cafodd Ioan ei wahodd ymlaen, a dywedodd: "Beth yw hwn?

Ioan was invited forward and asked, "What is that?"

"Cafodd y grŵp gyfarfod â chamaag.

The group met with astonishment.

Roeddych grŵpoedd hwnnw a diwylliannol mewn cyfranddaliadau.

These were groups with cultural shares.

Roedd ganddo'r ysbardun i siarad am ei angerdd am fythau ac anturio.

It sparked him to talk about his passion for myths and adventure.

O'r diwrnod hwnnw ymlaen, nid oedd Gareth yn wyddor i fwynhau cyfrifoldeb.

From that day forward, Gareth did not shy away from enjoyment.

Roedd siŵr ei bod hynny yn dod â chysylltiadau newydd yn llawr glas.

He was convinced that this brought new connections in the wide world.

Roedd ei angerdd yn adeiladu rhywbeth rhyfeddol ynddo.

His passion built something remarkable within him.

Roedd byth byth Allan o gwmni.

He was never without company.