The series tells the story of Charlie Chalk - a jolly clown who, after falling asleep whilst fishing out at sea, ends up on a strange island by the name of Merrytwit (as explained in the title sequence before each episode).
The pilot episode of the series (entitled 'Shipwrecked Charlie') finds Charlie having just landed on Merrytwit, and after making friends with some of its inhabitants, decides to stay and build a home there.