In the story, we follow the main character Min Ji Won, who suffers from amnesia, caused by an accident almost a year ago. While the "new" Min Ji Won is a shy person, who dislikes fish soup, we soon learn, that her past was totally different. Before the accident, she was the leader of a gang of four bullies. Through pictures, she learns about her 3 other "soul mates" and she wants to find out what happened to them. Whilst Min Ji Won tries to unravel the mystery, her former friends are killed one by one. Min Ji Won has little time left to find out what happened to her and the mysterious Su In.