When Akira Miyamoto learns that his older brother, Atsushi, is missing, his family begins to fall apart. The family business fails, and his father becomes an alcoholic. His two parents constantly compare Akira to Atsushi. Worse, Akira has a crush on a girl named Yuki, who already has a boyfriend, his friend Ken.
One day, Akira finds a girl unconscious in front of his house. The girl, Rei Aoyama, shows Akira Atsushi's ID card, claiming that Atsushi is alive. Rei explains that Atsushi is trapped on Higanjima Island, said to be inhabited by vampires. Akira invites his friends to help his brother, under the guise of a vacation to celebrate their graduation.
Upon arrival, vampires attack their boat and capture all of them except Rei. However, Akira escapes with his friends before vampires can drain their blood. On the island, he meets with Atsushi, who explains that the vampires are led by Miyabi, another vampire. Trained by Atsushi, Akira and his friends begin the battle against Miyabi and his vampire army in order to escape the island alive.
[Source: manga synopsis via Wikipedia]