The fates of Earth and the intergalactic community alike come to hang in the balance amid visions of doom in this middle volume. Picking up without a recap where Ashfall Legacy (2021) left off, half-human Syd and his multispecies squad of allies, reluctant and otherwise, flee but are ultimately forced to turn and face Capt. Reno and her associates. They, being full humans and therefore superstrong and (so they think) invulnerable everywhere except on Earth, violently believe that they are destined to rule rather than being genocidally wiped out. Even readers fresh from the opener may have trouble picking up the basic premise and the backstory, but that doesn't really matter as the pseudonymous authors stick to an easy-to-follow "spaceship chases and captures with occasional explosions in a pint-sized universe" sort of plot and give a cast featuring aliens diverse enough to include sentient gas and fungus plenty of chances to exchange banter and values. All of the actual agency continues to come from human or part-human characters who are, notwithstanding an impassive one with a Japanese name, uniformly White-presenting. A climactic battle leaves the human supremacist party at least neutralized, but thanks to an enigmatic space monster's "flickering whorls of temporal energy," troubling glimpses of a future Syd destroying a planet that looks a lot like ours leaves some unfinished business for sequels to settle. More stabs, grabs, and snarky confabs, with rising stakes to push readers on. (Science fiction. 13-17) Copyright (c) Kirkus Reviews, used with permission.