Yn nyfnder tywyll rhywle yng Ngogledd Cymru, roedd plant Ysgol Uwchradd Aberteifi ar drip maes.

In the dark depths somewhere in North Wales, the children of Ysgol Uwchradd Aberteifi were on a field trip.

Roedd cyffro yn yr aer.

Excitement was in the air.

Roedd Halloween yn prysur agosáu a roedd Gareth, bachgen chwilfrydig a chwareus, yn llawn brwdfrydedd.

Halloween was quickly approaching and Gareth, a curious and playful boy, was full of enthusiasm.

Ei ffrind, Carys, oedd wrth ei ochr.

His friend, Carys, was by his side.

Roedd hi'n ofalus, ond yn hoff o antur hefyd.

She was cautious, but fond of adventure as well.

Roedd y mynedfa i'r hen fwyngloddiau dan ddaear yn gul a thywyll.

The entrance to the old underground mines was narrow and dark.

Roedd y graig yn wlyb a'r awyr yn oer.

The rock was wet and the air was cold.

Roedd pelydr bach o olau yn disgyn ar y dail hydref melyn a oedd yn chwalu o gwmpas yr afanc.

A small beam of light fell on the yellow autumn leaves that scattered around the beaver.

Roedd yr athro yn siarad am hanes y mwynau, ond collwyd clyw Gareth.

The teacher was talking about the history of the minerals, but Gareth couldn’t hear.

Roedd yn ffocysu ar un peth yn unig - ardal sydd yn sôn fod ysbrydion yn crwydro.

He was focused on one thing only—the area rumored to be haunted by ghosts.

Cynnau lamp fflach oedd gwaith cyntaf Gareth.

Gareth's first task was to light a flashlight.

"Carys," ebe Gareth, "ma' 'na le dirgel yn wag gwnaethon nhw ddim sôn amdano.

"Carys," said Gareth, "there's a secret empty place they didn’t mention."

" Roedd ei lygaid yn pefrio.

His eyes sparkled.

"Dewch, does na'm rhaid clywed beth sydd ar deledu.

"Come on, we don't have to hear what's on TV.

Angen ei weld gyda'n llygaid ein hun.

We need to see with our own eyes."

"Cydiodd Carys yn ei llaw.

Carys took his hand.

"Gareth, byddai'n well gennym aros gyda'n grŵp.

"Gareth, we'd better stay with our group."

" Gwybodd oedd Gareth wedi gwneud ei feddwl i fyny.

She knew Gareth had made up his mind.

Os oedd yn cael trafferth, roedd hi'n benderfynol o fod yno i'w achub.

If he got into trouble, she was determined to be there to rescue him.

Cerddon nhw'n ofalus drwy'r llwybr tywyll.

They walked carefully through the dark path.

Roedd y sibrydion am ysbrydion yng nghefn meddwl Carys fel sbectol.

The rumors about ghosts lingered in the back of Carys' mind like glasses.

Ond nid oedd yn troi'n ôl.

But she didn’t turn back.

Roedd sŵn mwmian dwfn yn y meudwyaeth a'r ysgwyd creigiau a wnaeth ei calonnau rasio.

There was a sound of deep murmurs in the distance and the shaking rocks made their hearts race.

Yn sydyn, dyfod y ddau at gwmni agored, y siambr.

Suddenly, the two came upon an open company, the chamber.

Roedd yn teimlo'n greddf.

It felt instinctual.

Roedd yna helbul yma o'r gorffennol, ac roedd hynny'n achosi i'r ddau aros yn llonydd.

There was turmoil here from the past, and that caused the two to stand still.

Aeth Carys gam ymlaen ac edrychodd o gwmpas.

Carys took a step forward and looked around.

Roedd offer mwyngloddio hen wedi'i stocio yn y corneli.

Old mining equipment was stored in the corners.

Yn sydyn, clywodd Gareth ei hun yn siarad yn iawn: "Nid ysbrydion yw hyn, Carys.

Suddenly, Gareth heard himself speaking aloud: "These aren't ghosts, Carys.

Mae'n hanes.

It's history."

"Roedd hyn yn ddigon i droi'n ôl.

This was enough to turn back.

Ar eu ffordd allan, cofnodwyd y ddau llygad ar yr offer.

On their way out, the pair's eyes caught on the equipment.

Erbyn iddynt ddod i'r grŵp, roeddent yn ddigon cyffrous i ddangos eu darganfyddiad.

By the time they returned to the group, they were excited enough to show their discovery.

Roedd hyd yn oed yr athro'n synnu.

Even the teacher was surprised.

Diweddodd y dydd gyda nhw'n adrodd stori yr ardal ddirgel i'w cyd-ddisgyblion.

The day ended with them recounting the story of the secret area to their fellow students.

Dysgodd Gareth werth bod yn fwy gofalus, tra'r oedd Carys wedi sicrhau mwy o hyder wrth ddelio â sefyllfaoedd peryglus.

Gareth learned the value of being more careful, while Carys gained more confidence in dealing with dangerous situations.

Roedd heddiw yn gyfrinach llawn antur i'w gofio.

Today was an adventure-filled secret to remember.