Yujeong, who works as a night shift nurse at a general hospital's cardiology department, is now told that her 12th-grade younger sister, Kijeong, has been arrested by the police as a suspect in an infant abandonment case. Only then does Yujeong start to make desperate efforts to rescue her sister.。The film is said to be based on the emotional bonding between a boy and a dog and their love and affection for each other.。