On her way home during the holiday season, Jooyoung is called back to work. Having to work overnight is annoying enough, but then she gets stuck at a sobriety checkpoint.
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.
