The ubiquitous Company is Dr. Zeus, Incorporated; by the year 2335, it owns nearly everything. How? Well, it invented time travel (you can't go forward from your own time, but you can travel into the past and return) and a flawed type of immortality. So Dr. Z sent operatives back into prehistoric times to gather up some promising children, make them immortal, and form them into a secret network that will make all the right investments--and preserve species that, according to history, will become extinct. In 16th- century Galicia, a little girl, Mendoza, is threatened by the Inquisition--until she's rescued and recruited by Company operatives Joseph and Nefer and trained as a botanist. Then, in 1554, Joseph, Nefer, and Mendoza, posing as Spanish grandees, travel to England as part of the entourage of Philip of Spain, soon to be the husband of Mary Tudor, the fervent Catholic queen dedicated to returning Protestant England to the Vatican. Mendoza's mission is to study and preserve the rare plants growing in the gardens of Sir Walker Iden of Kent. But young Mendoza soon falls in love with Nicholas Harpole, Sir Walter's (mortal) secretary. Worse, as Mary's brutal and repressive grip on England tightens, freethinkers like Nicholas are being condemned and burned at the stake. Can--should--Mendoza save Nicholas? What of her mission, her immortality--and the Company? Baker's time-travel rationale genuinely hangs together. Add on the authentic 16th-century setting. Set it forth in a narrative that sparkles with wit: The upshot is a highly impressive and thoroughly engrossing debut.