Two children named Gracie Jenkins and Daniel Pender are best friends living on the island of Bryher. They enjoy sailing wooden boats that they make off the numerous beaches, but the tide carries their favorite one across to a forbidden bay. This is the home of a local hermit nicknamed the Birdman, whom all the children are forbidden to go near and whom none of the adults trust. This is partly due to him being born on a nearby island named Samson which all locals avoid, as they say it is cursed. On stormy nights he goes over to Samson and can be seen sending lantern signals out to sea.