In the turmoil of World War II, specifically during Japan's invasion of China, Jamie "Jim" Graham navigates a sheltered life in the Shanghai International Settlement, blissfully unaware of the impending chaos. As the occupation escalates, Jim's family evacuates, leaving him stranded and alone in their abandoned home, where he naively waits for their return while scavenging for food as the isolation stretches on.
In a desperate bid for survival, Jim attempts to surrender to Japanese soldiers but is dismissed and forced to fend for himself. His luck changes when he meets Basie and Frank, two American expatriates who initially plan to leave him to his fate. However, Jim proves to be resourceful and persuasive, convincing them to team up with him to loot the deserted houses in his neighborhood. Their escapades hit a snag when they unexpectedly find Jim's family home occupied by Japanese troops.
The trio is soon captured, taken to the Lunghua Civilian Assembly Centre in Shanghai for processing, and ultimately moved to an internment camp in Suzhou. As the war unfolds, Jim finds a sense of purpose by creating a trading network within the camp, striking deals even with the camp's commander, Sergeant Nagata. With the guidance of Dr. Rawlins, the British physician of the camp, Jim forms a father-son bond that becomes a crucial lifeline during his harrowing journey.
As 1945 approaches and the war’s end looms, Jim's world is rocked again when American fighter planes attack the camp. In the midst of this chaos, Jim collapses in despair, revealing his profound sense of loss as he admits he can no longer remember what his parents look like. The Japanese forces vacate the camp, and Jim begins to witness the true horror war inflicts on its victims.
In this dire situation, Jim forms an unexpected friendship with a young Japanese trainee pilot preparing for kamikaze missions. As they share this temporary bond, Jim watches helplessly as the pilot's dreams suffocate, a painful reminder of how war destroys the innocence of youth.
As the remaining prisoners of the camp make their way through the harsh landscape, many succumb to devastating fatigue, hunger, and illness. Their journey leads them to a large football stadium near Nantao, littered with the remnants of what was once Shanghai's vibrant life—all stripped away by the Japanese occupiers. Here, Jim finds a semblance of comfort in his parents' beloved Packard car, sharing a poignant night with Mrs. Victor, a fellow prisoner who soon meets her tragic end.
The echoes of the atomic bombing of Nagasaki loom over these moments, resonating with a haunting finality that reinforces the relentless brutality of war. Jim's path soon returns to the Suzhou camp, where whispers of Japan surrendering spread. During this time, he encounters a disillusioned Japanese teenager, who remembers him and offers a mango as a peace gesture, only moments before preparing his guntō for a different purpose.
The arrival of Basie, flanked by armed Americans intent on looting airdropped Red Cross provisions, leads to chaos where a misguided shot kills the Japanese youth, extinguishing his offer of hope. Rage and sorrow fill Jim, who, despite Basie's suggestion to find his parents, chooses to stay behind—his grief overwhelming.
Ultimately, Jim finds himself under the care of American soldiers, who place him in an orphanage. Although he reunites with his mother and father, the trauma of war's devastation has left Jim unable to perceive their presence, as if the very essence of his reality has been irreparably altered by this brutal chapter of his life.
