Leonardo and Tom are commissioned to paint a portrait of young bride-to-be Petronella,who is marrying thuggish,dishonest money lender Lucio solely to free her father from being in his debt. Macchiavelli recognizes Lucio as a man who hurt him when he was a child and,with the artists' help,concocts a plan playing to Lucio's greed by making him pay 100,000 florins for what they have told him is the alchemist's stone,to turn lead into gold. Having parted him from his money they then literally frame him for stealing a painting,freeing Petronella - who guesses 'Tom's' secret but says nothing.