Kisaragi Minori, who thought she had a happy family with her pure love since they were students and was married to her husband Yudai, was blessed with children, but the story begins when she finds out that her husband Yudai has been cheating on her for 15 years. Minori, who has vowed to take revenge on Yudai, who has another family, and on his lover, Riko Miyake, plots her revenge using Riko's son, Wataru.

Set in a high school senior class where students can now marry without parental consent due to the implementation of the new "18-year-old adulthood" law, this unprecedented school suspense drama explores first love, pregnancy, marriage, and even infidelity. Not only are the students of Class 3-C involved in affairs, but so are their parents and teachers...!? The protagonist of this work is Uemura Aoi, who transfers into Class 3-C at an elite high school after her parents get divorced due to her father's affair. The story depicts how she reunites with Tachibana Iori, a male student who was her first love and is now married to another classmate, and how they fall into an illicit affair. Their romance eventually spirals into a scandal that engulfs the school and their parents, leading to a gruesome tragedy.