Dan is bent on attending a “Zombie Wrestling” event, but Chris already has plans to take a cruise with Elise and her parents. In a failed attempt to sabotage Chris leaving, Dan inadvertently finds himself stowing away on an ocean liner as a fifth member of the family. Desperate to head back to Los Angeles, Dan manipulates the cruise activities with a vengeance, hoping to cause enough trouble to be sent home. But then he realizes that one lucky passenger will get the title of honorary Captain during a ship-wide contest, and decides to do anything possible to win the honor and use it to personally steer the boat back towards land. But when he succeeds, he manages to accidentally send the boat straight towards an oceanic black hole! Suddenly the whole family must put their differences aside to work together and save the ship!