Casey Ryback (Steven Segal) is a cook, but not just any cook. He’s a former US Navy SEAL who knows a thing or two about hand-to-hand combat, weapons fighting, and explosives. Ryback is forced to trade in his chef’s apron for any weapon he can get his hands on because terrorists have killed the captain (Patrick O’Neal) and taken over the ship. Ryback isn’t entirely alone on his mission as Jordan Tate (Erika Eleniak), a beautiful blonde, tags along for the ride. The odds seem to be in the terrorists’ favor, but now that Ryback is after them, they’ll be the ones Under Siege.