Having been diagnosed with a fast-acting form of dementia, contract killer John Knox (Michael Keaton) decides to liquidate his assets. On a job with his partner Thomas Muncie (Ray Mckinnion) Knox accidentally kills Muncie and a civilian in a fugue state due to his illness.

Knox’s son Miles (James Mardsen) comes to him for help after killing his daughter’s rapist in a rage. Knox cleans the scene and, with help from his friend Xavier (Al Pacino), proceeds to create a plan to frame himself for the murder, save his son, and ultimately pay for his crimes. The plan goes off without a hitch, but Miles is arrested for the murder. Furthermore, an escort that Knox had been seeing, Annie (Joanna Kulig), tries to rob him with three men only for Knox to kill them and tells Annie, disappointedly, that she would have received a cut of his money had she not betrayed him.

Knox tells Xavier to call the police, and he is arrested for the murders of the three men. The evidence of the other murder is tested and points to the fact that Knox set up his son. Miles is cleared, and when asked why his dad would do this, Miles (remembering an argument his dad created) said it was out of revenge for Miles turning him in for tax evasion.

Knox is convicted but, with his aggressive dementia, is moved to a medical facility where he will spend his final days. Thanks to Xavier, Miles and his mother Ruby (Marcia Gay Harden) get his father’s money. Annie, spared from death but disinherited, receives his classic book collection instead. The film ends with Knox looking out of a prison window, his mind lost, with only days left to live.