While her husband is away on a business trip overseas, Keiko lives with Yoshio, her husband's stepson. Recently, she has noticed Yoshio growing more and more physically mature. Though she repeatedly tells herself she mustn't view him as a romantic interest, she struggles to suppress her deep, uncontrollable feelings. Keiko grows jealous imagining Yoshio surrounded by his classmates, succumbing to temptation and drowning in raw desire. Eventually, their hidden emotions begin to surface, leading them to acknowledge their mutual attraction—and then, inevitably, to consummate it.