Bound by a debt, an illegitimate son moves in with his aloof cousin, unaware that their uneasy deal will spiral into a deep and dangerous obsession.
Il-jo and Jung-han’s lives spiral out of control after a hospital bill and an impulsive kiss bind them together. Debt, dependence, and blurred boundaries pull them into a dangerous closeness neither is ready to face.
Jung-han coldly reminds Il-jo that until the surgery debt is paid, everything about him belongs to him, forcing him to pay him back through housework. Yet beneath this control, their bond twists into a dangerous and forbidden intimacy.
Jung-han can’t understand why his desire for Il-jo runs so deep—but when Il-jo finally gathers the courage to confess, Jung-han shuts him down.
Jung-han visits Il-jo’s old home, and the two quietly revisit the warmth of their shared past, promising to meet again in Seoul. But when the day comes, Il-jo vanishes without a word—until night falls, and Jung-han finds him injured, waiting in the dark.
Jung-han and Il-jo finally define their relationship and begin their first real dates, but Il-jo’s insistence on keeping their love hidden fuels Jung-han’s growing insecurity and jealousy.
When Il-jo suddenly goes missing, Jung-han finds him at the hospital covered in bruises, realizing he’s been threatened. A fierce argument erupts between them, pushing their relationship to the brink.
On his uncle’s memorial day, Jung-han briefly reunites with Il-jo. Their parting pushes him to uncover the truth behind the threats — a trail that leads toward something far darker.
Il-jo’s past finally comes to light. When Jung-han falls ill with a high fever, Il-jo returns to care for him, and the two reaffirm their feelings — quietly making promises for the future they hope to build together.