Synopsis: Ji-Won is a bright young student, but something happened to her that left her with a blank memory. She has no recollection of who she is, her friends or her life before the incident. When her old friends mysteriously start dying one by one, she begins to investigate. As she slowly begins to piece together fragments of her past, strange and terrifying visions start to haunt her. She discovers that she was once friends with three other girls, and together they formed an impenetrable alliance. As more friends continue to die, she draws nearer to discovering the mystery that connects the present to a dark and horrifying past.