BZRK takes place in a world where new technology is changing the face of warfare. Biots, which are microscopic weaponry controlled by a gamer, fight on the Nano level. They infiltrate peoples brains, rewiring things, controlling people and changing memories.
Unbeknownst to governments and the general public a battle is being waged between BZRK and The Armstrong Fancy Gifts Corporation. Two factions who have the technology and both think that they are playing on the side of good.