In the seaside city of Riverfield stands Decelis Academy, home to seven mysterious boys sharing the same secret: They're vampires, hiding their murky pasts. When Sooha, a female student who hates vampires, transfers to the academy, the boys find themselves irresistibly drawn to her. As strange events shake the city, old sins and buried secrets resurface, and their world begins to fracture.

When Kyoichiro comes home, he hears that his 14-year-old son Kyosuke was stabbed to death. The person who killed Kyosuke turns out to be 13-year-old Mitsuru. The two boys were classmates. Due to Japan's juvenile law, Mitsuru will not receive commensurate punishment for his crime. Kyoichiro points his anger at Mitsuru and his mother Hatsumi, but Kyoichiro sees that Hatsumi also suffers from her son's actions.