One day, Shinya, a man living in an apartment building, happens to witness his neighbor, Saya, cheating on his wife. "She seemed so serious and pure, but she brought a man over... looks can be deceptive," he says. Shinya uses this as an excuse to come up with a despicable plan to get Saya to do what he wants, and puts it into action. He investigates the house and company of the man she is cheating with, and threatens that if Saya doesn't do what he says, he will cause trouble for him...