Michael Faraday, a history professor, is one of the residents of Arlington Road, a quiet street in the suburbs of Washington. Under serene appearances, he is recovering with difficulty from the death of his wife, an FBI agent, who died two years earlier following a blunder. Her son Grant is also haunted by the memory of his mother. They sympathize with their new neighbors, the Langs, a model family who has just moved into the pavilion opposite. But Michael is quickly intrigued by Mr. Lang’s behavior…