Young Moon who doesn't want to talk. And Jang Bum-young, a giant, expressionless man, who is not used to children, but with his innate patience, he encourages him to talk and generously supports him so that he can live like any other normal child. But what he doesn't know is that only in the pool can Jung-in be free, a place tightly controlled by Jang Bum-young. In junior high school, he realized that Jang Bum-young, who had become a natural part of his life, aroused his own desires. As he got older, he realized that it wasn't just an eruption of teenage passion, but he didn't have the courage to admit it. However.... Jang's obsession with Jung-in, a weak child who can be put away with a snap of his fingers, goes beyond the realm of mere surveillance, and it becomes a relationship where it is impossible to know whether Jung-in is being held by Jang or whether Jang is being held captive. by Jung-in. One day, while on a school trip, Jung-in is involved in an incident and is injured, and from that day on, the relationship between the seemingly ordinary guardian and the orphaned boy slowly begins to change.