In the Charenton (asylum) in 1808, the Marquis de Sade stages a play about the murder of Jean-Paul Marat by Charlotte Corday, using his fellow inmates as actors. The director of the hospital, Abbé de Coulmier, supervises the performance, accompanied by his wife and daughter. Coulmier, who supports Napoleon's government, believes that the play will support his own bourgeois ideas, and denounce those of the French Revolution that Marat helped lead. His patients, however, have other ideas, and they make a habit of speaking lines he had attempted to suppress, or deviating entirely into personal opinion. The Marquis himself, meanwhile, subtly manipulates both the players and the audience to create an atmosphere of chaos and nihilism that ultimately brings on an orgy of destruction.