Michael Durbin spends his first nine years with Maron Halvorsen, an aging religious fanatic who has decided that he is retarded and that God wants her to isolate him from the world. They live with Johann, her husband who is in the final stages of Parkinson's. As Michael gets older, he escapes to the second-floor where Maron, crippled by arthritis, cannot reach him. In the dark filthy second floor of the house, behind windows glazed by soot and dirt, he invents his own world, chants snatches of conversations he overhears, Bible verses, prayers. When Maron dies, he is discovered lying in a nest of old photographs, his face dirty and his hair wild. The press gives him the name of Rat Boy and he enters the County Farm with this nickname and receives many others. Here he learns about sex, friendship, betrayal and encounters religious fanaticism again. A parallel narrative records the attempt of Bernice Ylvesaker to write the life story of Michael Durbin as a favor to a fellow county home patient Joshua Brent, who has taken an interest in Michael.