Based on

Movies like Unfaithful Wife: In Front of Her Husband's Eyes (1994)

Mayumi Hirose lived with her husband Yasuhiro and younger sister Miki. Her girlfriend Yasuhiro, who was in the prime of his career, was busy every day, had many business trips overseas, and often returned home late at night. One day, my cousin Tadao came to Tokyo from his hometown. Tadao, who lost his family, ends up staying at Mayumi's house.