One of One

One day, Sujeong, a former lover, visits Hyung-gyu, who runs a Chinese house in the countryside. The two reunited after a long time confirming that their love for each other has not yet cooled down, and they start living together. Second, Min-gyu is anxious that Sujeong has come for Hyung-gyu's money. Hyung-gyu is angry with Hyung-gyu, who doesn't like him, and Min-gyu finally commits an unforgivable act. The youngest Dong-gyu, who felt the warmth of her mother from Sujeong, witnessed the relationship between Min-gyu and Su-soo. With her innocence destroyed, Dong-gyu no longer sees Sujeong as a woman, not her mother, and has an intolerable desire. However, Sujeong completely rejects Donggyu in order not to make any further mistakes. Then, Dong-gyu starts a dangerous joke to get Sujeong's attention...