Mae awyrgylch dirgel yn cwmpasu Castell Caerdydd, gan symud rhwng ei furiau canoloesol fel tarth trwchus.

A mysterious atmosphere envelops Castell Caerdydd, moving between its medieval walls like a thick mist.

Roedd yr awyrgylch yn brydfeth yr hydref gyda phlanhigion yn cwympo'n dawel ar y llawr cerrig o'u cwmpas.

The atmosphere was decorated with the beauty of autumn as leaves fell quietly onto the stone floor around them.

Roedd Gareth yn sefyll wrth y brif giât, ei wyneb wedi'i lewygu gan gyffro ac antur.

Gareth stood by the main gate, his face illuminated by excitement and adventure.

"Mae'r giât ddim yn agor," ysgrifennodd Carys i fyny wrth ei ochr.

"The gate isn't opening," wrote Carys up by his side.

Roedd ofn wedi diffodd ei thrywydd swyr cyffredinol.

Fear had extinguished her usual witty demeanor.

Neu afrad?

Or was it extravagance?

"Beth sydd wedi digwydd?

"What has happened?"

""Rhaid bod yn gyfrinach neu sgrîn i egluro hyn," meddai Gareth, ei feddwl wedi'i gyffroi gan hanes y castell, gan obeithio canfod eitem gudd.

"There must be a secret or a screen to explain this," said Gareth, his mind excited by the castle's history, hoping to discover a hidden item.

Roedd ei obsesiwn ag arteffactau hen yn ei blygu ar alwad gwirioneddol.

His obsession with ancient artifacts bent him toward a quest for truth.

Y ddau ffrind oedd wedi cael eu gafael yn y castelloedd harddiedig, gyda chyffro Carys i wynebu'r dieithr a phenderfyniad Gareth i ddarganfod.

The two friends were captivated by the magnificent castles, with Carys's excitement to face the unknown and Gareth's determination to discover.

Mae croeso i'r cyfan murluniau a choridorau tywyll yn arwain nhw i mewn i ddolennau o gysgodion.

All the murals and dark corridors welcomed them, leading them into loops of shadows.

Wrth i'r dydd fynd yn llwyd a'r haul yn gostwng, dechreuon nhw sylwi mawredd y lle.

As the day grew gray and the sun set, they began to notice the grandeur of the place.

"Dyma ein cyfle," meddai Gareth, yn parhau drwy'r porthau i ffwrdd wedi peintio.

"This is our chance," said Gareth, continuing through the painted gateways.

Er ei chwythlyd ac amser o rybudd Carys, roedd tafod ei ffrindyd yn ei atynnu ar y ffordd.

Despite Carys's caution and warning, her friend's enthusiasm pulled her along the path.

Wedi traul o awr yn crwydro, aethant i mewn i siambr gudd.

After an hour of wandering, they entered a hidden chamber.

Roedd arwyddion ar y waliau.

There were signs on the walls.

"Mae'n rhaid datrys y symbolau," meddai Gareth.

"The symbols must be solved," said Gareth.

Roedd Carys yn poeni, ond roedd yn gwybod nad oedd ffordd allan arall, felly cymerodd ran yn meddwl am yr arwyddion hyn.

Though Carys was worried, she knew there was no other way out, so she took part in figuring out these signs.

Wrth gydweithredu, daeth y cyfan i'w ddeall.

As they collaborated, it all became clear.

“Dyma yw’r dull,” cyhoeddodd Gareth yn llachar.

"This is the method," Gareth proclaimed brightly.

Wrth gael y cyfrinach roedd y siambr yn robyn fel mewn hud, gan ddatgloi'r giât a'u rhyddhau o'i ddalfa goch.

In uncovering the secret, the chamber opened like magic, unlocking the gate and releasing them from its firm grip.

Wrth eu traed, ar lafar serth castell, dan haulgŵyrw difyr, roedd yn deall y gwir stori.

At their feet, on the steep slope of the castle, under the amusing sunset, they understood the true story.

Roedd Gareth yn edrych ar Garys, gan sylweddolio bod y profiad a’r cwmni yn fwy gwerthfawr na’r aur a chwestiynau cudd.

Gareth looked at Carys, realizing that the experience and company were more valuable than gold and hidden questions.

Roedd y wibdaith yno i gofiwch am weddill ei ddiwrnod.

The excursion there would be remembered for the rest of the day.

Wrth fynd allan, clywodd y ddau sefyll a chwerthin.

As they left, the two stopped and laughed.

Roedd y mawl yn ddyfarnu lle oedd natur yn llawn iddo.

The praise was declared where nature was full to him.

Roedd muriau hen y castell wedi dangos rhywbeth newydd - arwydd rhyfedd o'n hwyl ni, yn fyw.

The ancient walls of the castle had revealed something new—a strange sign of our fun, alive.