It is 2012, the world has been struck down by a deadly virus. Humankind is in danger, and most of the adult population is dying. But children are set apart, and they seem immune until they grow older.
Out of nowhere, vampires come out and take control of the cities, taking children into custody, after all, it is imperative to have fresh blood to survive chaos. The remnants of humanity is in hands of blood sucking tyrants.
Yuuichirou Hyakuya is an orphan, he had a terrible childhood and sometimes he wished he was dead. He is taken to the Hyakuya Orphanage, where he met several children, among them, Mikaela, a friendly kid with a strong sense of unity.
Mikaela simply tells Yuuichirou that he has had a bad life so far, but now he is amongst family. Just like that, Mikaela does the unthinkable to give his family a chance to survive...