Each night Mungo reads his favourite story, a swashbuckling tale of danger, kidnap and rescue. But one night the hero, Captain Fleet, isn't there to save the day so Mungo decides to step in. He takes a deep breath and bravely jumps into the story and his very own pirate adventure. With a lot of bravery and a little help from the purple berserker bird, Mungo rescues Admiral Mainbrace and the plucky cabin girl Nora from the clutches of villainous Barnacle Bill and a whole host of horrible pirates.