Newly arrived in England after a time-volta of a century, Carter Paxton, his beautiful wife Lady Joanna, and their Timucua companions learn that the year is 1588 – and the Spanish Armada will arrive in July. Upon their return to London, they meet swashbuckling playwright Christopher Marlowe, top agent in Doctor John Dee’s intelligence bureau. Desperate to effect the release of his beloved Anastasia Petrovka from Dee’s custody and protect her from the Russian Inquisition’s assassin Vasilyev, the poet enlists Carter’s aid.
While Father Tranquillus searches for his descendants – Edwina, Mistress of the Royal Arsenal, and Cædmon, herbalist and mediciner – hard-drinking one-eyed Captain Sir Ralph Oldcastle seeks a shipwright willing to construct Paxton’s tusk-whale boats – submerged rams designed for stealth operations against the Spanish fleet. Meanwhile, Marlowe, pursuing his investigation into the shadowy Irkutsk Trading Enterprise, runs afoul of his old enemy Ingram Frizer, the ruthless Earl of Essex, and the Kurgan assassin Vasilyev.
Enlisting the help of Edwina, Paxton engineers the construction of an array of weapons ranging from Congreve rockets to marine mines. But the proposed weapon that astonishes the Mistress of the Royal Arsenal is Carter’s “sky galleon” – an airship mounting rocket launchers and Gatling guns. Learning of the buffalo hunter’s plans, Queen Elizabeth 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, the sky galleons and submerged rams completed, and Joanna six months pregnant with the Gemini, Destiny and Gawayne, Paxton has his hands full. When Anastasia’s former master, Count Anton Pretorius – alchemist and astrologer – 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 Spaniards’ suicidal assault on Tilbury to capture the Queen?