Jihyuk, the CEO of Taeseong Industries, finds a small daily pleasure in exchanging glances with Haegang, the quick-delivery part-timer near his office. A chance encounter leads to them having dinner together. While walking Haegang home that night, Jihyuk is suddenly attacked by an assailant and injected with a gender-altering serum.

Jihyuk wakes up in Haegang's house, faced with the shocking reality that he is now an Omega. Haegang stops Jihyuk from going to the hospital, claiming the outside world is too dangerous, and insists on caring for him, essentially trapping him inside...