The story is set in a far-future, multi-tiered society (centered on the asteroid-city Metro-1) where humanity has integrated with various alien species. The plot follows Akeldama "Blood" Bledsoe, the galaxy's premier bounty hunter, who is distinguished by a floating cloud of actual blood that serves as her "hair."
She is partnered with Thunder, an experimental, sentient, and often frustratingly pacifist A.I. rifle. The central conflict ignites when a mysterious and ultra-dangerous entity known as Prisoner X escapes from an orbiting maximum-security prison. As Blood and Thunder pursue the fugitive across strange alien worlds, they discover that the prisoner holds secrets regarding Blood's forgotten past - secrets that the ruling elite of Metro-1 have gone to great lengths to bury.
