During a family trip, Akari loses her return ticket, and Katayama and Akari are the only ones who can arrange it, so they end up staying together overnight in a shared room. However, this was all a plan to allow Akari, who has had a crush on Katayama since childhood, to be alone with him! Akari tells Katayama her pure feelings and presses for a physical relationship, but Katayama refuses sexual relations out of a sense of responsibility as a guardian. However, when Akari looks at him with moist Hitomi and says, "If it's just a kiss, it's not sex, right...?" and gives him a loving blowjob, Katayama's reason breaks down...