A daring, impulsive boy, Jack lives to sail, have adventures and get in trouble. When the Noronic docks at Ward Island, he and his friends gather to admire it, but you need an invitation from one of the passengers to come on board. Jack spots Henry, a quiet, lonely boy from Boston with not much knack for making friends, and talks him into inviting Jack and his group to tour the ship.
The Noronic is everything Jack has dreamed of, a grand Great Lakes cruise ship, equipped with the latest features, its top three decks full of fashionable passengers. Jack vows that one day he will captain this ship. And in the course of the tour, Jack and Henry become friends.
Jack can't sleep that night and looks out towards the pier. To his horror, he sees that the ship is on fire and without thinking he tears down to the harbour and takes out the island's only motorboat, hoping to help the passengers. People crowd the deck because the only way off the ship, three decks below, is already engulfed. Jack sees Henry on deck and calls to him as Henry's dad helps him jump in the water. Jack is able to pull Henry and many others from the water although Henry's dad is lost. Another rescue boat joins him and between them they save 51 people, although 118 perish. Jack is a hero of sorts, but many people blame him for taking the boat out on his own instead of calling someone older to help.