During a suffocating summer, Natsuki's husband brings home his younger hometown friend Kiyoshi, who has just arrived in Tokyo and needs a place to stay. His rough appearance worries her at first, but living together reveals a pure and gentle adult man. Kiyoshi also falls for Natsuki's kindness and mature allure. Unable to contain their feelings, they surrender to a summer of raw emotion, deep kisses, and adultery.