Plot
Michael Faraday is a history professor at George Washington University, teaching a class on American terrorism and living in Reston, Virginia with his young son Grant. Since the death of his wife Leah, an FBI agent, Michael remains friends with her partner Whit Carver, and is dating his former graduate student Brooke Wolfe. Finding a boy named Brady injured by fireworks, Michael rushes him to the hospital and meets his parents, Oliver and Cheryl Lang. They discover they are neighbours on Arlington Road and their sons become friends, joining a scouting troop together.
Oliver appears to lie about an alumni letter delivered by mistake, and about a blueprint Michael notices in the Langs' house. Michael becomes suspicious, intensified by Oliver's anti-government sentiments and his interest in Leah's death, but reluctantly lets Grant join Brady on a scouting trip. He presents his class with the case of Dean Scobee, who died bombing a federal building in St. Louis months earlier despite no record of terrorist activity. Bringing his students to the site of the Ruby Ridge-style standoff where Leah was killed, an emotional Michael excoriates the FBI for mistakenly identifying their target as a potential terrorist.
Michael determines Oliver lied about where he attended college, and was actually born William Fenimore in the same Kansas town as the deceased Oliver Lang, and 16-year-old William was arrested for trying to blow up a government office. Michael convinces the Langs' children to let him into Oliver's home office while their parents are out, and he finds the suspicious blueprint hidden behind a Gateway Arch schematic, but is nearly caught when Cheryl returns. Brooke dismisses Michael's concerns, suggesting his terrorism studies and Leah's death have made him paranoid and obsessive.
Oliver confronts Michael for investigating him, explaining that the attempted bombing was a regrettable act as an angry teenager: the government cut off his family's farm from their water supply and his father committed suicide, staged as an accident so the family could collect his life insurance payout, but they lost their land. To escape his past, William assumed the name of Oliver Lang, a childhood friend who died after college. Brooke later spots Oliver switching vehicles, and follows him to a warehouse where he loads his car with mysterious cases. She leaves Michael a voicemail, but is confronted by Cheryl.
That night, Michael learns Brooke has been killed in an apparent car accident, and is comforted by the Langs, apologising to them for his mistrust. However, a call from Whit reveals that Michael's answering machine has been erased, and he warns Whit to investigate his suspicions about Oliver. Visiting Dean Scobee's father, who is certain his son could not have acted alone, Michael notices a photo of Dean with Grant's scout leader. He realizes Grant has been taken by Oliver, who declares that he and his sinister group killed Brooke; he murdered the real Oliver to assume his identity, and threatens Grant's life, warning Michael not to interfere with their plans.
Whit finds nothing incriminating about Oliver, but confirms that Michael received a call from the payphone Brooke used. Driving there, Michael spots the Langs' associates and tries to follow them, but sees Grant inside their van. Michael is intercepted and beaten by Oliver, who asserts his group's mission, but Michael overpowers him and realises he intends to blow up the J. Edgar Hoover Building. Warning Whit, Michael pursues the van into the building's garage, only to discover he is chasing a decoy. He finds the bomb planted in his own trunk as it detonates, and Oliver watches from a distance as the blast destroys FBI headquarters.
With Michael and Whit among the dead, the Langs and their conspirators successfully frame Michael as a lone wolf terrorist — just as they did with Dean Scobee — seeking revenge on the FBI for Leah's death, supported by accounts of his increasingly erratic behaviour. The orphaned Grant moves in with relatives, unaware of his father's innocence, while Oliver and Cheryl prepare to move their family to another safe suburb for their next attack. [4]
