It was late at night. The old-fashioned doorbell echoed through the run-down building, ringing on and on. Worried the noise might disturb the neighbors, Jee Heejin carefully opened the front door to see what was going on. “Who is it…?” “Hey… long time no see.” Jee Heejin and Jee Hyunwoo, who once lived as step-siblings for five years after their parents’ remarriage, meet again after five years apart. Now a handsome medical student returning in triumph, Hyunwoo approaches the drunken Heejin and whispers that this time, they should become family not as siblings, but as husband and wife… and in this forbidden reunion, Heejin is forced to make a life-altering choice.