In the tradition of Mark Twain's Connecticut Yankee in King Arthur's Court and Edgar Rice Burroughs' Mars novels, medievalist Stanley Lombardo's Paxton versus the Armada delivers a tale of adventure, romance, and thought-challenging alternative history in the third installment of The Crosstime Adventures of Carter Paxton. Newly arrived in England after a time-volta of a century, Carter Paxton, his beautiful wife Lady Joanna, and their companions discover that the year is 1588 and the Spanish Armada will arrive in July. Upon their return to London, they meet swashbuckling playwright Christopher Marlowe, an agent in Doctor John Dee's intelligence bureau. Marlowe introduces the buffalo hunter to Doctor Dee, who challenges him and Joanna to prove they are who they claim to be; in an audience with the Queen, they convince the skeptical Elizabeth of their identity.
Meanwhile, Father Tranquillus searches for his descendants -- Edwina, Mistress of the Royal Arsenal, and Cædmon, herbalist and mediciner at Saint Waltrudis Paupers' Hospital. Upon entering the hospital, the poor, indigent patients acclaim the priest as "Saint" Tranquillus, to Edwina's chagrin and anger; however, Cædmon is more willing to accept their ancestor's identity. Off on his own errands, one-eyed, hard-drinking Captain Sir Ralph Oldcastle endeavors to get His Majesty's Ship Constitution and their prize Spanish galleon, the Santa Eulalia, released from impoundment and, furthermore, to locate a shipwright willing to construct Paxton's submerged rams - the first in the cowboy's proposed arsenal of weapons against the Armada.
At the Royal Arsenal, Paxton consults Edwina to help him construct an array of armaments ranging from Congreve rockets to Colt's marine mines, but the proposed weapon that astonishes the Mistress of the Arsenal is the Carter's "sky galleon" - an airship mounting rocket launchers and Gatling guns. Learning of Carter's plans, the Queen demands a sky galleon of her own, which she vows to captain with an all-woman crew.
With the Armada cruising up the English Channel, Marlowe's beloved Anastasia Petrovka stalked by a fanatic assassin of the Russian Orthodox Inquisition, and Joanna six months pregnant with the twins, Destiny and Gawayne, Paxton has his hands full. When Anastasia's former master, Count Anton Pretorius, arrives in search of her, Doctor Dee enlists his aid in conjuring a tempest to scatter the Spanish fleet and save England - but will any of them survive the Armada's suicidal assault on Tilbury to capture the English Queen?
