In the South Pacific in 1944, U.S. Marine Corporal Allison, Robert Mitchum, and his reconnaissance party are pulled from a U.S. Navy submarine only to be spotted and fired upon by the Imperial Japanese Army (IJA). The submarine’s captain is forced to dive, leaving the scouting team behind. Allison drifts for days in a rubber raft and eventually washes up on a small island. There he discovers an abandoned settlement and a chapel inhabited by a single figure: Sister Angela, Deborah Kerr, a novice Irish nun who has not yet taken her final vows. She has been stranded on the island for only four days, having arrived with an elderly priest to evacuate another clergyman, only to find the Japanese had arrived first. The frightened natives who had brought them to the island disappeared without warning, and the priest died soon after.
For a time, the island seems quiet, but a detachment of Japanese troops soon arrives to set up a meteorological camp, forcing Allison and Sister Angela to hide in a cave. When Sister Angela cannot stomach the raw fish Allison has caught, he bravely sneaks into the Japanese camp to scavenge for supplies, narrowly avoiding detection. That night, they witness flashes from naval guns in a distant sea battle, the glow punctuating the danger that still surrounds them.
The Japanese unexpectedly depart, and Allison confesses his love for Sister Angela, asking to marry her. But she reveals that her engagement ring is a symbol of her forthcoming final vows, keeping true to her calling. The moment of tenderness is tempered by projections of fear and fate, and their celebration soon gives way to frustration as Allison sinks into sake-fueled intoxication. He blurts out that her vow seems pointless given their predicament, saying they are “like Adam and Eve” on this isolated island. <br>
> like Adam and Eve.
She runs out into a tropical rain and falls ill from the strain, while Allison, now sober and remorseful, finds her shivering and carries her back. The island again becomes a danger when the Japanese return, forcing them back into the cave. Allison sneaks into the Japanese camp to fetch blankets, but in the process he kills a soldier who discovers him, triggering a larger alarm. In response, the enemy set fire to the surrounding vegetation to flush them out.
When a Japanese soldier discovers the cave, Allison and Sister Angela face a stark choice: surrender or die from a hand grenade thrown inside. The explosion that follows is not a grenade but a bomb, signaling the Americans’ impending assault on the island. Allison notes that the landing will not be easy, because the Japanese have brought four artillery pieces and concealed them well on the island.
In the ensuing battle, accompanied by a sense of fate and duty, Allison works to sabotage the invading guns. He disables the artillery during the barrage before the American landing by removing their breechblocks, a dangerous act that saves many American lives. He is wounded in the process, and afterward the missing breechblocks puzzle the Marine officers who discover the sabotage.
With the island secured, Sister Angela and the wounded Allison share a poignant farewell as the Marines begin their occupation. The encounter leaves Allison reconciled to Sister Angela’s devotion to Jesus, while she reassures him that their bond will endure as close “companions.” Eventually, Allison is found and transported aboard the ship, with Sister Angela walking beside him as they continue their separate paths toward a future beyond the island.
