While staying at his uncle's island lodging, Mitsuru enters into a secret sexual relationship with his cousin Chitose. The arrangement expands when Chitose's shy, honor-student friend Yasumi reveals her own hidden lust and joins them. After a summer of intense passion and shared secrets, the three form an unbreakable bond that carries them from the isolated island to a new life together on the mainland.
Natsume discovers that his seemingly innocent girlfriend, Yumisaka, harbors a hidden fetish for being filmed and engaging in risky sexual encounters. Simultaneously, Yumisaka's friend Seta begins a clandestine, dominant relationship with Yumisaka's younger brother, Shuu, leading him down a path of sexual awakening while his sister remains completely oblivious.
Moriyama finds himself entangled in secret, passionate affairs with two different girls who hide their true natures behind a facade of innocence. After a successful confession leads to a physical relationship with the transfer student Izumi, he also discovers that his prim tutoring student, Hinamachi, has been using their lessons as a cover to satisfy her own hidden sexual cravings.