Kazuko, a former national-level competitive swimmer who is drowning in heavy debt, flees from loan sharks and seeks refuge with Aota, an old school friend who now works as a high school teacher. Aota agrees to hide her, but in exchange, he forces her to act as the coach for the school's struggling swimming club, which is preparing for an upcoming inter-school meet against a neighboring school. With the swimming club severely lacking members, Kazuko uses her looks and charms to recruit students into joining. As she works with the team, their swimming performance and lap times begin to improve drastically. Beneath the surface of the sports-themed setup, the swimming meet involves corrupt underhanded deals, dragging Kazuko and the students into a web of adult conspiracies orchestrated by school figures.