The drama is adapted from the mystery novel of the same name written by Kanae Saminato in 2019. It tells the story of a new film director Hasebe Ka (Kitagawa Keiko) consulting a new screenwriter Kai Mahiro (Yoshioka Riho) about a film script. The root cause is the "Sasazuka-cho family murder case" 15 years ago, in which a man who stayed at home stabbed his high school sister to death and set fire to his parents, killing them.