Zette McGee is a private investigator, and former cop, in a habitat on Ganymede. She abruptly retired from the force, rather than risk exposure of a personal secret. McGee is called out of retirement by a frantic phone call from android Kell Fallow, who knows her secret, and who swears he did not kill his family. Before Fallow can reach her, he is killed by a bomb in his gut.
At every step in the investigation, McGee, and Gideon Smith, a friend with a shadowy past, are stopped cold. It is the work of a firemind called Hydrogen Steel. Think of an artificial intelligence that has had eons of time (about a hundred years in human time) to grow and evolve. It can do a lot more than just read minds, for instance. Wherever they are, it can disable their ship, leaving them stranded in space. It can infect their neural implants with all sorts of major viruses. It can send an android that looks identical to McGee to destroy her residence. It can create intruders out of thin air, then disappear into thin air, to kill anyone it wishes. Hydrogen Steel can also infect McGee and Smith with bombs identical to the one that killed Fallow, forcing them to get quantum scans of their brains, and those scans downloaded into new bodies.
Hydrogen Steel's mission is to prevent any release of information regarding how the Earth disappeared years before. There wasn't any rubble from its destruction, just "poof." Another firemind, Otaru, finds out the truth, but knows that it will not survive the expected battle with Hydrogen Steel.
This is a gem of a novel. It's a really good mystery/thriller; how does anyone deal with an entity that can reach into your DNA, and do something nasty? It's also quite mind blowing, and is very much worth reading.