The Mask of Death

The Duke is dead. Long live the new Duke!
Having at last polished off the Duke, Piero is ready to assume power in fair Florence. As we saw last week, he poisoned the Duke and blamed it on Milan, meaning that Florence and Milan will almost certainly go to war. Lorenzo is upset about the Duke's assassination and is determined to fight in the war to avenge him. 

Alone with the dead: Leo and Verrocchio make a cast of the Duke's face

 To tie up loose ends Placidi is sent to deal with the failed assassin Scarpa who demands payment; Placidi only laughs at him. Scarpa next shows up, threatening to tell all unless Piero delivers his promised fee. Naturally, he only ends up enraging Piero who decides to dispose of the wily assassin before he can open his big mouth. When Leonardo is hired to make the death mask of the deceased Duke, Tom is suspicious of Piero's motives. Piero's plot becomes obvious when he tells Leo that Florence will lose a war against Milan unless they use Leo's amazing inventions. Meanwhile, the cast of the death mask cracks and turns a weird red color. Leo realizes that the blemishing is caused by some strange chemical, possibly poison. Leo tests several poisons to see if they match the substance on the mask. He is able to duplicate the cracking effect with a sample of cyanide. 

"Hmm, pretty sure that's not supposed to happen."

To obtain more concrete evidence, Leo and Tom sneak into the crypt to take scrapings from the Duke's mouth, but Piero catches them in the act. Leo quickly makes up a lie to cover his tracks and they are escorted out before he can get evidence. Leo gets the name of the attending physician Dr Pentangeli from Lorenzo and goes around to ask him about the death. He confides in the doctor who agrees to help him do a post-mortem, warning Leo to not tell anyone else about his suspicions. Naturally, the good doctor hotfoots it to Piero and alerts him to Leo's detective work. Piero calls Scarpa and tells him he can have his money if in return he commits a previously unscheduled murder.

Scarpa, winner of The Most Trusting Assassin Award

 Leo is startled when Piero shows up at the post-mortem feigning concern at the possible poisoning of the Duke. The post-mortem is suddenly interrupted by Scarpa who pretends to be targeting Piero, but shoots Dr. Pentangeli as he is (unlike Leonardo) dispensable. With his dying breath the doctor tries to tell Leo that Piero hired the assassin, but dies before he can reveal his secret. Leo examines the arrow and realizes that it is covered in cyanide. His suspicions are put to rest as he now believes the Milanese killers dipped the arrow that killed the Duke in poison. 

"You see Leo, it's because I'm just so very evil."

He agrees to help Piero and designs terrible war machines to use in the upcoming war against Milan. Placidi disposes of the assassin, who in the end turned out to be stupid enough not to see the double-cross coming, but smart enough to warn Placidi that the Duke will one day kill him as well since he knows all his secrets. Placidi declines to burn the poison stained handkerchief that Piero used to wipe the Duke's mouth, clearly hoping to use it one day as insurance.