Chester Chestnut is a happy little chap, but sometimes, even the happiest of chaps get worried or nervous, and when this happens Chester's tummy starts to hurt. Follow the journey of Chester Chestnut as he learns about his anxious thoughts and feelings, where they come from and how to control them.

Mae Chester Chestnut yn hogyn bach hapus, ond weithiau, mae hyd yn oed y plentyn hapusaf yn teimlo'n bryderus neu yn nerfus, a phan fo hyn yn digwydd mae bol Chester yn dechrau brifo. Dilynwch daith Chester Chestnut wrth iddo ddysgu am ei feddyliau pryderus, o ble maen nhw'n dod a sut i'w rheoli nhw.