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

Leonardo continues his search for the Book of Leaves; Lorenzo is forced to make sacrifices when Pope Sixtus takes aggressive measures against Florence; Lucrezia looks for new alliances in 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.