Several months after the events of Skyward, the defiant humans of Detritus have gained a foothold on the orbital platforms surrounding the planet. Hyperdrive is a still a mystery, so they’re strategically stuck, with little intelligence about the Superiority which is keeping the humans trapped. One day, a mysterious ship carrying a previously unknown humanoid alien crash lands on Detritus, and Spensa must quickly set off on a covert infiltration mission she is ill-prepared for, to the enemy settlement of Starsight, a major Superiority settlement.
The bones of the story are fine, and carry the main arcs of both Spensa herself and the conflict forward. However, the books seems to drag for much of the middle. Interesting events occur but the pace is off, with perhaps too much exposition about Superiority politics and how they have led to this. The final section picks up, however, with a satisfying and action-filled conclusion.