When Naoko was a freshman in high school she was kidnapped and imprisoned by a man who lived next door. For one month, she went through hell. Finally, she killed the man and escaped.

The film stars Mitsu Dan as a 31-year-old woman named Naoko who leads a double life. While in high school, Naoko was kidnapped by a male neighbor and kept in captivity for a month before she barely managed to escape by killing him. Saddled with this trauma, Naoko grows into adulthood and becomes a doctor specializing in fertility treatments during the day while spending her nights as a professional masochist at an SM club.