Rock, a Black Shooter soldier who was bullied to death in her previous life, patrols the Hazama, a purgatory between Heaven and Earth, with her partner Ron, a sentient weapon that can transform to match the job. Their work is extracting trapped souls from phantoms, twisted manifestations that selfish or wounded people become if left alone too long, so those souls can move on. Rock's methods put her at odds with Dead, a rival Black Shooter who destroys the phantoms' souls outright instead of saving them.