Young Jim Mulholland can't believe his good luck: He has signed on as a cabin boy to the world's finest ocean liner, the Titanic, and can't wait for the history-making voyage across the sea to America. As part of his duties Jim is in charge of the ship's cat, a beautiful tortoiseshell that also appears happy to be on board. He calls the cat by the ship's construction number, 4-0-1, certain that she will bring him good luck. And he's delighted when 4-0-1 shortly gives birth to a litter of kittens. But once the ship's trial runs are completed and it's ready to launch to sea, Jim notices that 4-0-1 is nowhere to be found. He's got to find her-the Titanic can't cast off without her lucky cat. Jim is faced with a decision that will affect the rest of his life.