Each night Mungo reads his favourite story, a swashbuckling tale of danger, kidnap and rescue. But one night the hero, Captain Flinn, isn't there to save the day so Mungo decides to take action. He takes a deep breath and bravely jumps into the story and his very own pirate adventure. With a lot of courage 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.