Minesweeper

During peacetime, Lieutenant Richard Houston deserts to escape overwhelming gambling debts and abandons his Navy career. He then takes up life as a wandering hobo, drifting from place to place and avoiding his responsibilities.

The attack on Pearl Harbor jolts Houston back into service, and he re-enlists under the assumed name Jim 'Tennessee' Smith. He is assigned to active duty to defend the nation.

Houston is assigned to a minesweeper, where he carries out numerous successful defusings in San Diego harbor while keeping his true identity hidden. His skill earns him respect among the crew.

A romantic rivalry develops as Houston vies for the affections of Mary Smith, niece of Chief Petty Officer Fixit Smith, with Seaman Elliot Nash. The tension is intensified by their Navy duties and proximity.

While gambling, Houston overstays his shore leave and Smith, who has taken over his post, is killed by a mine. The event underscores the cost of Houston's past AWOL and the collateral damage it causes.

Houston confesses to Mary that he gambled to raise money for an engagement ring. He is crestfallen to realize that his AWOL contributed to Smith's death.

Feeling tempted to desert again, Houston returns to his base to take on one last dangerous mission. He steels himself to prove his loyalty and redeem his past.

Lieutenant Ralph Gilpin discovers that Houston is the deserter and that his true identity under the alias is James Smith. This revelation places Houston in a precarious position as a prisoner-at-large within the chain of command.

In a show of resolve, Houston volunteers to help clear the shipping lanes of mines so a troop ship can depart safely. He accepts the danger despite his status as prisoner-at-large.

Houston and Nash dive in San Diego harbor to locate a mine that responds to the sound of an aircraft overhead, rising from its tether as the sound travels. The moment highlights the mine's vulnerability and the risk the divers take.

Nash relays the information to Gilpin, but Houston cuts Nash's oxygen line, forcing the crew to haul him up. The mine explodes, killing Houston.

On the launch, Nash tells the crew that Houston was a true hero, acknowledging the sacrifice made. The crew grasps the gravity of Houston's double life and ultimate act of courage.

Gilpin realizes a countermeasure: flying a Catalina plane low over the water triggers the acoustically sensitive mines to release, allowing the minesweepers to blow up each mine. The operation clears the harbor for the troop movement.

The Secretary of the Navy awards the Navy and Marine Corps Medal posthumously to Gunner's Mate First Class James Smith for his sacrifice. The ceremony cements his legacy as a hero who gave his life to protect others.