Second in a just-about independently intelligible alien-warfare trilogy (Conquest, 2014) from Connolly (the Charlie Parker mysteries, etc.) and wife Ridyard, who offer a helpful short summary in the first couple of pages.
Advanced human-aliens, the Illyri, have conquered the Earth. Internally, the Illyri Military and the Diplomatic Corps tussle for dominance and plot to ally themselves with a third power, the Nairene Sisterhood, a secretive female society of knowledge-brokers—who bear an uncomfortable resemblance to Frank Herbert’s Bene Gesserit. Resistance to the conquest, however, smolders, particularly in Scotland, where Syl Hellais, the governor’s daughter and the first Illyri to be born on Earth, raged against the constraints imposed on her. Syl—having learned that many senior Illyri are infected with an alien parasite that apparently enhances their abilities—escaped and became involved with resistance fighter Paul Kerr. Having been captured, Paul and others agreed to be trained as fighters for the Illyri and were sent millions of light-years away. Syl was sent to join the Sisterhood in their convent, the Marque, a moon orbiting the Illyri home world. Paul vows, despite all obstacles, to return and claim Syl, but he soon learns that Illyri politics are vastly more complex and dangerous than anybody on Earth dreamed—and that there exists another alien race of unknown powers and purpose. Syl, meanwhile, concealing her immense psychic powers, learns that the Sisterhood is encouraging younger sisters to develop psychic powers and to employ them with sadistic cruelty. And they know more about the alien parasites than anybody suspects. This satisfyingly complex backdrop spins up into an intriguing web of plots and mysteries as the main characters grow along with the story, along with virile if sometimes rather implausible action. More disappointing is the way the authors allow an initially taut narrative to accumulate flab and crisp prose to degenerate into hackneyed gloats and phrases.
Should particularly appeal to the more youthful section of the audience, devotees of the Kevin Anderson–Brian Herbert epics and suchlike.