In 2008, Archer Monroe (Patrick Warburton), the patriarch of a wealthy and powerful political family in New York City, passes away suddenly.
Archer’s estate is divided among his family: Catherine (Connie Nielsen), his wife; William (Chace Crawford), his son, a politician running for reelection; and Lauren (Lily Collins), his daughter, a Manhattan District Attorney. Privately, the family attorney Harold Thewlis (Michael Beach) gives Lauren a message from her father that leads her to a secret bunker beneath the family property, where she finds a stranger (Simon Pegg) being held in captivity. The man identifies himself as Morgan Warner and says he’s been held prisoner for thirty years.
While Morgan is sleeping, Lauren takes a sample of his fingerprints and sends them for identification. Morgan claims he was once a friend and business partner of Archer’s, until one night when they were driving drunk and ended up killing a pedestrian. At Archer’s insistence, they covered up the crime before Archer took Morgan prisoner to stop him exposing the murder. In the intervening years, Archer treated Morgan like a confessor and admitted many of his secrets.
Morgan directs Lauren to where the pedestrian’s body is buried. Lauren also follows Morgan’s clues and finds Archer’s longtime mistress, with whom he had a son, as well as evidence that Archer paid bribes to get his children elected to public office. Lauren is eventually convinced to set Morgan free, and directs Harold to set up an offshore bank account and charter a private jet so Morgan can disappear.
Lauren’s fingerprints come back with a match and the file is sent to the Monroe house. Catherine finds the file and is terrified by the sight of Morgan, whom she identifies as “Carson” and calls an “evil man”. Lauren also discovers that Harold has been murdered, and by the time she returns to the Monroe house, Carson has abducted Catherine and taken her to the bunker.
Carson subdues Lauren and it’s revealed that thirty years ago, Carson drugged and raped Catherine, and Archer was taking Carson somewhere to kill him when they ran down the pedestrian; furthermore, Carson was responsible for Archer’s death, using poison Archer had intended to use on him.
Lauren fights back and, in their struggle, Carson claims he is really Lauren’s biological father before Catherine seizes his gun and shoots him dead. Together, Lauren and Catherine pour gasoline throughout the bunker and set it alight, destroying all evidence of Carson’s captivity.