The MS Poseidon, a luxury ocean liner, is making a transatlantic crossing. Former New York City Mayor and firefighter Robert Ramsey (Kurt Russell) is traveling with his daughter Jennifer (Emmy Rossum) and her boyfriend Christian (Mike Vogel) to New York, soon to be engaged. Also on board is Navy submariner-turned-professional gambler Dylan Johns (Josh Lucas), architect Richard Nelson (Richard Dreyfuss), Maggie James (Jacinda Barrett) and her son Conor (Jimmy Bennett), stowaway Elena (Mía Maestro), and waiter Valentin (Freddy Rodriguez).