Author: Bethan Gwanas.

We follow Cadi, her mother and brother, to the seaside, where Cadi disagrees with her mum and goes to sit in a water pool. Suddenly, she is drawn into the sea by Mabli the mermaid, where she helps to find a present for King Neptune. But she has to look out for the white shark! 

Awdur: Bethan Gwanas.

Mae Cadi'n mynd i gael picnic ar lan y môr. Wrth iddi orwedd mewn pwll dwr cynnes, braf, mae'n cael ei thynnu i lawr ac i lawr i waelod y môr mawr! Dyna pryd mae'n cwrdd a'i ffrind newydd, Mabli'r fôr-forwyn. Ond rhaid cadw'n ddigon pell oddi wrth ogof Morlais, y Morgi Mawr Gwyn.