The story revolves around a group of people gathered on a former warship for a one-week cruise trip. The passengers come from various cultural and social backgrounds, including the power-driven middle-age senator and his son, a couple of newly-weds, a mysterious old man, three prostitutes, and a gang of violent gangsters. At first, the aggressive behaviour of the thugs and their leader is directed at the first-class passengers, but then more and more indiscriminately against the rest of those on board. Very quickly, one act of violence follows another.