Ji-Na works as a contract employee at a hotel. She appears to live a normal life, but, internally, she is filled with an inferiority complex. One day, she hears that her older sister Ji-Hyun is missing. Ji-Na goes to Rose Mansion Apartment, where her parents live. There, she faces unexpected cases. She can't trust the residents at Rose Mansion, who seem suspicious. Ji-Na seeks out the truth in her sister's disappearance with the help of Detective Min-Soo . Min-Soo is the only one who believes Ji-Na.