A detective who can’t help but love a serial killer! Is there a way for all of us to be happy… Inha, who lived a lonely life during college due to his personality that prevented him from maintaining connections, is approached by Sehwa, who confesses her feelings. Surprised by Sehwa's confession, whom he had a crush on, Inha accepts it. Relying on Sehwa and gaining confidence, Inha becomes a police officer and joins a task force currently investigating the most notorious serial killer. However, he discovers that the serial killer is Sehwa. Inha learns that Sehwa commits murder to see the expression on her face in desperate situations, but unable to imagine living alone without Sehwa, he ultimately chooses to stand by and watch.