During the Pacific War, Lt. Cmdr. Ken White orders the submarine Tiger Shark to crash dive to evade a Japanese aerial attack. CPO Boyer begs him to wait for the captain, Cmdr. Josh Rice, who remains topside, but White refuses, and Rice (his good friend) and the quartermaster are lost. When they surface, they learn that the war is over. No one besides Boyer blames White—not even the captain's widow and father.
White marries Carol and stays in the Navy after the war. Everything seems fine until he is assigned to show a reporter around who is doing a story about the Navy's mothball fleet. By chance, the submarine catching the journalist's attention is the Tiger Shark. The newsman mentions that the officer who ordered the dive must feel like a heel, and White's guilt resurfaces, straining his marriage.
> must feel like a heel
Then Boyer is assigned to his unit. When Boyer sees White, he immediately requests a transfer. As the Tiger Shark is being recommissioned, White sends him there. A fire breaks out on the submarine, trapping a man in a compartment. Boyer wants to charge in to his rescue, but White makes him go “by the book” and put on a protective suit first, fueling Boyer's hatred.
White is about to resign from the Navy to escape the ghosts of his past, but changes his mind at the last moment. As a result, Carol decides to leave him. North Korea invades South Korea the same day, starting the Korean War. White is given command of the Tiger Shark. He sets sail from the Mare Island Naval Shipyard for the war as soon as the submarine is ready. Boyer is a disgruntled member of the crew.
When they rendezvous with an aircraft carrier, White is given a special mission. A colonel and his special intelligence unit are in possession of vital information, but are prisoners of war. A rescue mission is being mounted; White's job is to land men at two points to knock out enemy coastal installations in advance of a paratrooper airborne assault on the prison camp. White's part of the raid is led by Commander Peter Morris, a family friend. However, after dropping off Morris's unit first, one of the Tiger Shark's engines begins overheating, endangering the timing of the second landing. To make up lost time, White makes the risky decision to enter the mined harbor. Once he sees the signal that the mission has been successful, he surfaces in order to notify his admiral, even though that exposes the submarine to fire from shore batteries. When the Tiger Shark is hit and starts sinking, White orders the crew to abandon ship. He and his men are picked up along with the freed prisoners.
His demons finally exorcised, he later attends the launching of another Tiger Shark with Carol, their baby and Boyer.
