The Pazzis make their move; Leonardo gambles for the future of Florence; Riario makes progress in his quest for the Book of Leaves.

Leonardo employs his genius to restore order to Florence, while Pope Sixtus unites powers against them. Elsewhere, Nico attempts to withstand Riario's temptations.

Leonardo's quest for the Book of Leaves continues; Pope Sixtus deals aggressively with Florence, leaving Lorenzo to make sacrifices; and Lucrezia undertakes an alliance-forming mission to Rome.

Leonardo attempts to navigate the Atlantic without maps; Lucrezia is smuggled into the Vatican for an important meeting; Lorenzo's identity is discovered during his trip to Naples.

Leonardo makes an unexpected discovery in the New World. Lorenzo attempts to save Florence with the help of an old flame. Clarice struggles to retain control of the Medici Bank.

Leonardo and Riario enter the Vault of Heaven whilst Lorenzo takes part in King Ferrante's bloody games. Lucrezia runs into the Turk whilst making her way to Constantinople.

Leonardo and his allies face deadly threats as they search for the Book of Leaves; Carlo helps Clarice; the Sultan's son is intrigued by Lucrezia.

Leonardo and Riario have to deal with a near passing experiance, while Zoroaster and Nico come up with a plan to escape. Bayezid travels to Rome on a diplomatic mission.

Leonardo returns to learn that Duke Federico has been ruling Florence with an iron fist; a sinful Riario seeks redemption; King Ferrante negotiates with Lorenzo.

Italy prepares itself for an attack from the Ottomans. Riario is been stalked by danger. Nico is the only person who can control what happens to Vanessa.