In the quest for forbidden knowledge «homo sapiens» screwed up again - in 2012 deadly virus broke out , which began destroying humanity. Somehow died only grown ups, and then, out of nowhere, vampires came and the remaining children were herded into their underground city, declaring that henceforth the "little people" live under the protection of fanged owners, paying blood. Sharp guy Hyakuya Yuuichirou lived since 4 years
and knew it was time to break out - along with his brother called Mika and the whole "family Hyakuya", a group of children who grew up in the same orphanage. Of course, vampires are easily caught up and killed the fugitives...