Duk-soo lost his father and younger sister while taking refuge during the Korean War. He leaves for Germany to work as a miner and enters the Vietnam War. He wishes to find his sister.

Dong-hyun is a high school student. One day, he falls from the rooftop and bumps into Pan-soo who is a passerby. Pan-soo is a member of a criminal organization. When the two men wake up in the hospital, they discover that they have switched bodies.