Kang-wook, a law student at Seoul National University, finds himself in a tight spot financially after losing contact with his family in North Korea. He sells his own blood at a hospital to make ends meet, and there he meets and grows close to nurse Jin-young. As Kang-wook faces financial difficulties, Ki-yong, a son of a landlord's agent, appears and tricks Kang-wook into joining left-wing activities. Ki-yong's true identity is revealed by Yoon-ae, a friend from hometown, leading to his arrest. Meanwhile, Kang-wook and Jin-young marry with the blessings of Professor Park and their friends, while Kang-wook's friend Do-hyeon struggles to hide his feelings for Jin-young. Their sweet days together come to an end with the outbreak of the Korean War, separating them. Jin-young, unable to wait for Kang-wook any longer, decides to flee the war with Do-hyeon. Kang-wook, hiding at Yoon-ae's house, is eventually arrested by Ki-yong and the leftists, who had been freed from prison.