Torpedo Run

In October 1942, ComSubPac orders the submarine Greyfish to hunt a Japanese convoy. The target includes the carrier Shinaru, a ship that helped lead the Pearl Harbor attack. The escort also carries a transport ship with American prisoners from a Philippines internment camp, among them Doyle's wife and child.

During the pursuit, Doyle realizes the escort includes a transport ship carrying American prisoners from the Philippines. He discovers that among the prisoners are civilians, including his wife and child, heightening the personal stakes of the mission.

Lieutenant Archer Sloan tries to persuade Doyle to let him handle the torpedo attack, hoping to spare Doyle the burden of risking his family. Doyle insists on remaining in command, aware of the personal risk and the mission's gravity.

Doyle commits to the strike, firing torpedoes with the aim of hitting the transport while missing the carrier. The crew carefully tracks the torpedoes, counting seconds to determine if they struck the intended target.

One torpedo grounds the transport, and the Japanese make no effort to rescue the survivors. Women and children cling to wreckage as the imprisoned group meets a grim fate in the sea.

Doyle pursues the Shinaru into Tokyo Bay, intent on sinking the carrier. The pursuit intensifies the danger as enemy defenses readiness and countermeasures rise to meet the threat.

The Greyfish fails to sink the Shinaru during the Tokyo Bay engagement and endures a relentless barrage of depth charges. After the ordeal, the submarine returns to base at Pearl Harbor.

Back at Pearl Harbor, Sloan meets with Admiral Setton alone. Sloan argues Doyle should remain in command and notes Doyle's continued readiness to serve as second-in-command despite the guilt over destroying the civilian transport.

Setton offers Sloan a promotion and his own command, but Sloan refuses, insisting that Doyle remains fit for command and deserves to keep him as second-in-command. The offer highlights the power dynamics within the submarine force.

The Greyfish is assigned a quiet, out-of-the-way patrol off the Alaskan coast. Doyle fears he has been betrayed by Setton and Sloan, and he openly reveals that he already knew about Sloan's offer for command before the meeting ended.

News places the Shinaru on a course for Japanese-occupied Kiska Harbor. The Greyfish proceeds to intercept the carrier again, bracing for a dangerous engagement.

An initial encounter with the Shinaru results in the submarine's periscope being disabled and the radio antenna destroyed. Doyle plans a second attack under deteriorating conditions, relying on alternate methods to strike.

Doyle conducts a second torpedo attack as a blind run with little chance of success. The Greyfish is forced to the ocean floor by a depth-charge attack as the crew fights to survive.

With the submarine doomed, the crew uses Momsen lungs to escape the sinking hull and reach the surface. They are taken aboard the American submarine Bluefin, awaiting a chance to confirm their fate.

On the Bluefin's deck, the captain looks through the periscope and, via intercom, informs Doyle and Sloan that the Shinaru has sunk. The grim confirmation caps the perilous mission and its personal costs.