Leonardo - Season 1 Episode 12 Fireball

Piero summons Leonardo to his palace and suggests that,as both are 'men of vision',they should work together to produce one of the inventions in Leonardo's notebook. It is a toy but Machiavelli is led to believe that it is a bomb,with which Piero intends to kill the duke of Florence at his birthday party. Leonardo humiliates himself when the invention turns out to be the harmless toy and not the bomb about which he warns the duke. Piero has,of course,kept the real bomb for himself.