A case of insomnia swept across the globe. As a side effect of the drug developed to suppress this sickness of causes unknown, the "bloodivores" were born. Born from bloodivore and human parents, protagonist Mi Ryu was known as "The Child of Hope" tying bloodivore and humankind together. However, when Mi Ryu is arrested as the principal offender in a bank robbery, he is taken to a special prison operated by the Bureau of Special Threat Management for observing bloodivores.