“He's cheating on my girlfriend.” That's what Koyuki, Yuki's wife, is told. A few days after this accusation from her husband's best friend Shinji, word comes that the two of them are meeting at a love hotel. Half-doubting, she goes to the hotel — and there is Yuki, walking in leaning on a woman. Choosing to believe in her husband's innocence, Koyuki agrees to help with the investigation, and when she stakes out the hotel again, obscene noises start coming from the room. Shaken by what looks like her partner's betrayal, she can't push Shinji away when he moves on her, and crosses a line. But all of it was a trap her husband's best friend had laid for the couple...