Shiori's best friend suddenly asks her to have sex with the woman's boyfriend because she wants to watch him with someone else. Since he knows nothing about the plan, Shiori is told to make the first move, and the unusual request soon piques her interest. When he comes home and the two are left alone, he quickly gives in to Shiori's seduction. She enjoys herself while exchanging secret signals with her watching friend—but which of the three is really the most turned on?