Ji Na (Lim Ji Yeon) 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 (Yoon Kyun Sang). Min Soo is the only one who believes Ji Na.