Rising artisan Leonardo da Vinci is commissioned by the powerful Medicis to create an Easter spectacle in Florence. Da Vinci is hired to engineer war machines. A mysterious Turk intrigues Leonardo.

Leonardo continues his quest for the Book of Leaves. The Pope's nephew arrives and meets his spy. Leonardo's war designs fail, causing a rift with the Medicis. The Pope learns of Leonardo's prowess.

Riario discusses his defeat with the Pope and a mysterious prisoner. An outbreak of demonic possession at a convent is blamed on the Medicis, but Leonardo searches for a rational explanation.

Bechhi is arrested and accused of being a spy for Rome. The armies of Rome and Florence face off, and Leonardo reveals his latest weapon.

Lorenzo orders Piero da Vinci to defend his estranged son in court. During a performance for visiting royalty, Leonardo surprises the corrupt judge. Back at his workshop, Leonardo is surprised by the Turk.

A clue from the Turk about the Book of Leaves sends Leonardo to Wallachia, where he encounters Vlad Dracula. Lorenzo and Piero meet the Duke of Urbino. The search for the true spy continues.

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.