Jun-shik, a Korean living under Japanese occupation, dreams of becoming an Olympic marathon runner. He and Tatsuo, a Japanese youth from a wealthy family, develop an intense rivalry that culminates in a controversial race where Jun-shik's victory is denied by the authorities. World War II erupts, and both young men are conscripted into the Japanese Imperial Army. Their paths cross again when they are forced to fight side by side in the brutal battles across Manchuria and Siberia. The harsh realities of war test their endurance and challenge their loyalty as they struggle to survive while grappling with their mutual animosity.

As they endure the horrors of combat, Jun-shik and Tatsuo's relationship transforms from fierce rivalry to reluctant cooperation. Captured by the Soviet Army, they are sent to a labor camp where their unity is further tested. Their journey continues as they are plunged into new conflicts and captured once more by different armies, causing them to grapple with their own identities and kinship amid the chaos. Their odyssey takes them across various fronts of the war, and the two men must decide if their shared humanity can overcome the hatred sewn in their past.