Zoichi Kanoe, a synthetic human working for Toa Heavy Industries, rides through ruined cities on a talking motorcycle whose AI, Fuyu, is fused into its frame. His mission is to find people who can resist the N5S virus, a Mars-born infection that turns the population into disfigured Drones. Racing the rival Data Recovery Foundation, which wants the virus to spread, Zoichi reaches the containment facility on 9JO to extract a girl named Ion Green before the outbreak consumes everything.