Shishimai Wataru, a full-time househusband, was an excellent detective but retired after the murder of his wife, and lives a peaceful life while raising his only daughter in high school. One day, he is suddenly summoned by Motomura Shuta, a young man suspected in a "serial kidnapping case," and assigned to investigate the case. Moreover, Motomura suffers from Dissociative Identity Disorder (DID), a disorder in which several personalities appear interchangeably.