The conclusion of the trilogy. Best to read the first two first. Particularly for the interchapters, which rove over the backstory.
Gideon and Sofia are, separately, trying to penetrate LaRoux Industries. A security alarm has them first joining forces -- Sofia tries to distract guards with Gideon, and it gets out of hand -- and he helps her flee to her refuge. And leaves a means of contact.
When LaRoux security catches up to her, he comes to her aid again, and the story weaves onward. Both their reasons for going against LaRoux come out, in the course of buying take-out, meeting others who turn out to care also, soldiers who follow conspiracy theories, someone rescued by a soldier, an opening for a museum and an invitation to it, learning to dance, a lot of hacking, and more.