Over two thousand passengers and crew climb aboard the luxury ocean liner Poseidon, to see in New Year's Eve. A colossal wave comes out of nowhere to swallow up vessel, turning it upside down. A few survivors are caught in the ship's ballroom and struggle to reach the deepest bowels of the ship which are now at the top. The must fight their way through debris, fire and the powerful ocean. They know it's their only chance to get out.