B. Max invents a boat, the SS B. Max, and the dogs help him figure out how to make it float. Raggs invents an underwater world and everyone pretends to be an underwater animal. Raggs has so much fun; he decides he wants to be a dog-fish. The dogs find a way to teach him that pretending is fun, but it is important to be himself and that the life of a dog-fish is not as much fun as he thought.