So-Yeon suffers from claustrophobia due to a traumatic incident that occurred to her as a child. So-Yeon is still treated for her condition to this day. She works as a groomer at a pet shop. One day a cat named Bidanyi comes into the store. The next day the owner of Bidanyi is found dead in an elevator. So-Yeon by request from police officer Joon-Suk takes the cat home. Shortly after So-Yeon starts to see a mysterious young girl. She becomes frightened. Then So-Yeon's good friend Bo-Hee is found dead. Near Bo-Hee there is a cat which Bo-Hee recently adopted from an animal shelter. So-Yeon now fears for her own life. So-Yeon and Joon-Suk investigate deeper into the mysterious case. There is a hidden story related to the cats.