Ed Harris, David Duchovny and William Fichtner star in this thriller set on a submarine during the Cold War. Captain Demi (Harris) has secretly been dealing with health issues that are affecting his grip on reality. Having made mistakes in a past mission which resulted in the loss of his former crew members, he is now on his final assignment on a missile submarine. KGB agent Bruni (Duchovny) and his team unexpectedly join the mission, putting Demi and executive officer Kozlov (Fichtner) on edge. When the real reason for Bruni's presence becomes clear, Demi realises he will have to take action in order to prevent the outbreak of war.