Gullible and adventure-loving litte Johnny Cat most of all wants to go to sea, but he is still far too young. He works as an apprentice to the old pirate, Captain Karlsson, who owns a boatyard. Daily the Captain tells the lad blood-curdling tales of derring-do on the high seas. Karlsson's old friends, Pirate Jenny and Captain Kid, also impress Johnny with their swashbuckling stories. How is Johnny Cat to know that they've made up every word....?