Kato and Koshimizu, a boss and subordinate working in the same department, are currently in a secret office romance. When a young man transfers in, Koshimizu is tasked with looking after him. Despite it being for work, the close physical proximity and their bonding over inside jokes make Kato increasingly moody... The cool Kato, who had never shown much emotion until now, can no longer restrain himself and becomes forceful, driven by his jealousy...!