The conspiracy is seen through the eyes of fictional court jester Moschino, but refers to actual historical figures from the Renaissance period. As in other historical films by Florestano Vancini, the only thing that is made up is the narrative construction of the film. Vancini is always mindful of historical truth: if he hadn't become a director, he would have loved to become a historian.
This film tells the story of the feud that, between 1505 and 1506 caused a schism setting brothers Alfonso (Ruben Rigillo) and Ippolito (Vincenzo Bocciarelli), against Giulio (Giorgio Lupano) and Ferrante (Carlo Caprioli), in a struggle for power after the death of the their father, Duke Ercole I of the Este dynasty.
The film also portrays life at court, including such characters as Lucrezia Borgia (Marianna De Micheli), Ludovico Ariosto (Fausto Russo Alesi), and the young Titian (Gianantonio Martinoni). Through the character of the jester, (a marvelous Manlio Dovì, who, coming from cabaret, brings a highly theatrical performance) and the story of his friendship with a peasant girl (Sabrina Colle) we get a good picture of what everyday life was like for the poor: as victims of the absolute power wielded by royalty they were reduced to conditions of abject misery.
An important role in the film is also that of Count Boschetti (Mariano Rigillo) who brings Giulio and Ferrante into the conspiracy and who ends up literally drawn and quartered in the square. The brothers are pardoned and condemned to life imprisonment.
Moschino, the court jester is, against his will, drawn into the conspiracy, but is found not guilty of lèse majesté and freed.
Passed from service to Giulio to Alfonso, he meets his end as the result of a prank: as thanks for curing the Duke of an annoying attack of the hiccups by throwing him into a fountain, the jester receives the death penalty.
At the very moment of his execution at the gallows, it is revealed that it is merely a joke by Alfonso, but the revelation comes too late, and Moschino dies of fear. Like a historical romance, the film mixes fantasy and reality in a tale which is at once comedy, tragedy, and farce. The title, as Vancini points out, represents a metaphor for life: jest, laugh, die.
In And Laughingly Killed Him Vancini's intention is to show both sides of the Renaissance: that of the nobility and the ruling classes, ready to do anything for power, and that of the rest of the populace, the subjects and peasants, a social situation which led to continued episodes of violence.