Graham the galleon scares Toot with stories of a sea monster who lives just beyond the harbour. Toot hides inside the dry dock, but when his friend Paula the trawler runs into trouble at sea, he is forced to be brave in order to help her.

Toot finds an old bell with the aid of a sonar device. Meanwhile, Bethan and Caleb's first sandcastle of the summer is washed away.

Toot causes an oil spill when he is rushing to deliver it to Mr Chilly, the ice cream van. An emergency clean-up is declared and Toot tried to make amends for his carelessness.