Widowed when his FBI agent wife was killed by a right-wing group, Michael Faraday (Jeff Bridges), professor of modern history and an expert on domestic terrorism, becomes obsessed with the culture of these organizations, especially when his new neighbors, Oliver (Tim Robbins) and Cheryl Lang (Joan Cusack), start acting suspiciously. At first the Langs seem like the perfect addition to the neighborhood. But all is not what it seems. When Faraday's private sleuthing turns up dark secrets from Oliver's past, the mystery deepens and the question looms; is Faraday just consumed by fear and driven by paranoia, or has a lethal conspiracy been born on Arlington Road? In short order, Faraday's suspicions about his newfound friends will lead to tragic and irrevocable consequences.