Jin is a talented undercover agent for the National Police Agency’s public security department. He would do anything as part of his job, even if it meant getting in a physical relationship with female persons of interest. While on an infiltration mission, he reunited with his former lover Yayoi, who was also a police investigator. Despite knowing that they shouldn’t be close to one another, they ended up having sex once again, resulting in him to re-evaluate his work and love relationships.