For most of her crew, the Retaliate's Baltic cruise is a routine one, and her sixteen nuclear missiles no more than a silent threat to the Russians. But the submarine's captain, Commander Shadde, is obsessed with the communist menace, and haunted by the memory of his one act of cowardice. As the submarine approaches the end of her voyage, a letter from his wife threatening divorce pushes Shadde to the brink of madness - in a vessel where nuclear war is just a touch of a button away.