Da Vinci is commissioned by the Medicis to create an Easter spectacle in Florence. Later, he's hired to build war machines, and meets a mysterious Turk.
Leonardo's quest for the Book of Leaves continues, and his failing war designs for the Medicis cause a rift between them. A papal spy, Riario, is defeated by Leonardo and returns to Rome.
Riario discusses his defeat with the Pope and a mysterious prisoner, while Leonardo searches for a rational explanation to an outbreak of demonic possessions that is blamed on the Medicis.
Bechhi is accused of spying for Rome and arrested; Leonardo unveils his latest weapon; Florence's army squares off with Rome's. At a party in his honor, Leonardo is arrested for sodomy.
Piero, Leonardo's estranged father, is ordered to defend his son in court. Later, Leonardo turns a corrupt judge during a performance for visiting royals. The Turk makes an appearance.
The Turk's clue about the Book of Leaves leads Leonardo to encounter Vlad Dracula, while Lorenzo and Piero meet with the Duke of Urbino. Later, the search for the Medici's spy intensifies.
Leonardo builds an underwater suit and breaks into the Vatican through the sewer. He meets the Pope and the mysterious prisoner. Giuliano reveals the identity of spy in Rome.
The Pazzis plan to overthrow the Medicis on Easter. The Turk tells Leonardo the location of the Book of Leaves. Later, Lucrezia admits a startling secrect, and Leonardo saves the Medicis.
