Under the surface of everyday life, an illness ravages all of humankind, turning everyday people into wild, mindless beasts. To counter this, Venators take to the streets and clean out the vermin under the cover of night. Kafka Ikari - a young man who can't remember his past - is one of many of these hunters. However, after a near-death experience, Kafka finds himself pulled into a conspiracy deeply rooted in his lost memories, one that could forever shift the fate of humanity itself.