Author: David De Thuin; Welsh Adaptation: Alun Ceri Jones.

Series: Llywelyn Fychan.

Llywelyn Fychan finds an old book about his school which says a riddle-solving brainy pupil will one day find a hoard of treasure. Llywelyn is game, but he doesn't want the treasure for himself - he wants it to spare his school from cutbacks which are due to close the establishment.

Awdur: David De Thuin; Addasiad Cymraeg: Alun Ceri Jones.

Cyfres: Llywelyn Fychan.

Mae Llywelyn Fychan yn dod o hyd i hen lyfr am ei ysgol sy'n sôn y bydd un disgybl, sy'n ddigon clyfar i ddatrys pos cymhleth, yn dod o hyd i gelc o drysor. Mae hyn yn sbarduno Llywelyn i fynd i chwilota - nid er mwyn cadw'r trysor iddo fe ei hun, ond i gadw'r ysgol rhag cau unwaith ac am byth.