A book-length amplification of the last pages of The Forge of God (1987). After Earth's destruction by the planet-eating machines of the Killers, the Benefactors--another group of aliens--create the Ship of the Law crewed by Earth survivors (it's the Law that victims of the machines must pursue vengeance). Martin, a young boy in the previous volume, now near-adult, is the Pan (i.e., leader--the rest of the crew are Lost Boys and Wendys). We see them drilling endlessly for the future skirmish and arguing over whether the mothers (Benefactor robots who maintain the ship) have told them everything they need to know to do the Job. They find several star systems that seem to be the Killers' home; they attack one and are repelled by an anti-matter counterattack, escaping only by a high-tech hairsbreadth. Then they continue to a second system, and are joined in their effort by a fascinating alien race who are aggregate intelligences braided of individual snakelike animal-level parts. Internal strife among the humans makes more difficult their task of penetrating the overwhelming technological superiority and deceptiveness of the Killers; but they ultimately destroy the entire system via a combination of superweapons and aggressive brute force, leaving the moral tone highly ambiguous. Lacking both the real-world anchoring of its predecessor and the transcendent ending it promises (finding a new home planet--a third volume?), and telling far more than it shows. Despite some interesting ideas, then: slow and unrewarding.