The story unfolds in Nanjing during the tumultuous period of late 1937, where John Rabe, a German businessman and the head of a local Siemens branch, has made the city his home for nearly thirty years alongside his wife Dora Rabe. As the impending transfer of management responsibilities to his successor, Werner Fließ, looms, John faces a significant professional challenge that heightens his anxieties about returning to Berlin. This concern escalates amidst a farewell ball held in his honor when the city is suddenly bombarded by Japanese aircraft. In a moment of urgency and compassion, Rabe opens the company gate to assist the frightened civilians seeking safety from the chaos.
As the next day dawns, the aftermath of the bombing reveals a city in distress. Among the remaining foreigners in Nanjing, Dr. Rosen, a German Embassy Attaché with Jewish heritage, shares his insights regarding the establishment of a safety zone in Shanghai for civilians. This proposal receives enthusiastic support from Ambassador Trautmann and Valérie Duprès, who serves as the director of the International Girls College. In light of these circumstances, Rabe is appointed as the chairman of the international committee, bolstered by his status as a German ally of the Japanese. The formation of this committee is initially met with skepticism from Dr. Robert Wilson, the American head doctor at a local hospital, who holds ideological biases against the German-influenced Rabe.
Tragedy strikes when Rabe sends his wife back to Germany. Heartbreak ensues when the ship she is on is bombed, leading to the loss of all on board, potentially including his beloved Dora. Meanwhile, the Japanese military captures a significant number of National Revolutionary Army soldiers during fierce confrontations outside Nanjing, ultimately leading to the brutal invasion of the city. The international committee, led by Rabe, successfully negotiates the recognition of the Nanjing Safety Zone with Japanese authorities, providing refuge to hundreds of thousands of civilians—an overwhelming number that stretches their resources thin.
As the situation deteriorates, the committee members, including the steadfast Valérie Duprès, refuse to abandon the Chinese soldiers concealed in the attic of her college, showcasing their resilience amidst the harsh realities. Amidst the chaos, a bond forms between Rabe and Dr. Wilson as they share drinks, sing, and even play the piano together, finding comfort in camaraderie. The committee celebrates Christmas with the arrival of care packages from the outside world, igniting hope. A particular package—an unmarked Gugelhupf cake—causes Rabe to faint upon realizing it must be a secret message from Dora, indicating her safety.
However, despair sets in when Dr. Wilson discovers Rabe’s diabetes, leading him to secure a vital supply of insulin from the Japanese forces. As the new year dawns, circumstances grow dire, pushing Rabe to spend his last savings on supplies for those in their care. The situation escalates with the approach of Japanese troops, but in a profound act of solidarity, the local civilians and the international committee form human shields to protect the vulnerable.
As tension mounts, the arrival of Western diplomats and journalists aboard a steamboat signals a turning point just before conflict can erupt. The film culminates with Rabe bidding farewell as he traverses the ruins of Nanjing, escorted by Japanese personnel toward the harbor. In a revelatory moment of connection, he is celebrated by the Chinese populace before finally being reunited with his wife Dora on the pier, sealing a poignant end to a harrowing chapter in their lives.
