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In 2012, the world allegedly comes to an end at the hands of a "human-made" virus, ravaging the global populace and leaving only children under the age of thirteen untouched. It is at this time that vampires emerge from the recesses of the earth, likely followed by age-old horrors of the dark thought only to be myth.

Yuuichirou Hyakuya is finally reunited with his childhood friend Mikaela Hyakuya, whom he had long presumed to be dead. Upon their reunion, however, he discovers that Mikaela has been turned into a vampire.