The novel is set in London in 1886 and follows the life of Mr. Verloc, a secret agent. Verloc is also a businessman who owns a shop which sells pornographic material, contraceptives, and bric-a-brac. He lives with his wife Winnie, his mother-in-law, and his brother-in-law, Stevie. Stevie has a mental disability, possibly autism, which causes him to be very excitable; his sister, Verloc's wife, attends to him, treating him more as a son than as a brother. Verloc's friends are a group of anarchists of which Comrade Ossipon, Michaelis, and "The Professor" are the most prominent. Although largely ineffectual as terrorists, their actions are known to the police. The group produce anarchist literature in the form of pamphlets entitled F.P., an abbreviation for The Future of the Proletariat.