Beautiful girl so-yeon (Park Minying) has been plagued by claustrophobia for many years. As long as she stays in a confined space, she will feel great depression and terror. Fortunately, the cute and naughty little animal soothed her fragile soul, and now so-yeon works as an animal makeup artist in a pet shop, living a dull and happy life. But her life was quickly disrupted by an accident when one of her guests died in the elevator shortly after leaving, and so-yeon had to take care of her pet cat Xiao Bu for the time being. From this moment on, she can often see short-haired girls with dark faces and ubiquitous faces. Her spirit almost broke down, but the strange things became more and more intense, and finally even her good friend Baoji died for no reason. So-yeon vaguely felt that all the terrorist incidents that had happened so far had something to do with the mysterious Brook.