The Longitude Chronometer, a device that will change the world, is stolen from HMS Petrel by pirates working for the legendary but supposedly long dead Edward Teach - better known as Blackbeard. On board the Petrel is Tom Lowe, an English spy working undercover as ship's surgeon. Lowe's mission is to prevent the Chronometer from falling into the hands of pirates... and if the opportunity should arise, to assassinate Blackbeard.
Blackbeard's plans are complicated when a popular Pirate Captain comes to town and violently disagrees with his grand design. For his master plan to survive, Blackbeard must weigh the risks of ridding himself of a dangerous old friend. Meanwhile, trying to gain insight into the Commodore's mysterious endgame, Tom Lowe finds himself an unlikely instrument of Blackbeard's will.
Having learned of Blackbeard's plans to attack innocent civilians in Jamaica, Lowe devises a way to report back to his spymaster, William Jagger. But having done so, Lowe discovers that Jagger might be an even greater madman than the Commodore. The time has come to make a choice between two evils. Which way will he jump?
Lowe plots to kidnap Blackbeard and deliver him to the English authorities, believing this to be the only way to save the people of Santa Compana from the mad wrath of William Jagger. Meanwhile, Jagger visits an insane asylum, believing a patient there will be the key to finally defeating Blackbeard.