Set in London in 1886, the novel follows the life of Adolf 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,[6] which causes him to be 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.