David Baldacci’s mystery novel, Memory Man, is the story of a man who has lost the ability to forget. Amos Decker starts out as a football player for the Cleveland Browns. During his first game, he suffers a head injury that alters his brain.

Decker spends time at the Cognitive Research Institute, where his condition is diagnosed as a combination of hyperthymesia—which Decker refers to as his inner DVR (that is, digital video recorder)—and synesthesia. He is incapable of forgetting anything, even the smallest details about an event, and his brain categorizes information using a system of numbers and colors. Unlike people who are born with these attributes, Decker is a manufactured savant.

His new mental condition makes it difficult for Decker to relate to other people, and he’s only able to function because his wife and daughter act as a grounding influence. Decker builds a successful career as a detective until the night someone murders his wife, brother-in-law, and daughter. Decker’s first impulse is to commit suicide because he doesn’t know how he can function without his family. 

Decker can’t forget the horrific murder scene, and he goes into a downward spiral, losing his job and home. He eventually recovers enough to become a private investigator. His home becomes a rented room at a Residence Inn.

Decker drifts aimlessly through life for almost two years until the day his former partner, Mary Lancaster, shows up to tell him someone has confessed to Decker’s family’s murder. Decker is determined to confront the suspect, Sebastian Leopold.

As Decker stands outside the police station, trying to figure out a strategy to see Leopold, Decker notices a scene of unusual activity: There has been a shooting at Mansfield High School, and every officer at the station house is deployed to the scene.

Taking advantage of the confusion, Decker talks his way into Leopold’s cell. Their conversation is disappointing: Leopold is vague and appears to be on drugs. Decker is convinced that Leopold’s confession is false.

At this same time, a reporter named Alex Jamison pesters Decker for an exclusive on Decker’s reaction to the confessin. When Decker refuses, Jamison publishes an inflammatory article linking the suspect with Decker and suggesting that Decker conspired to murder his own family.

Though Decker’s old boss, Captain Miller, reprimands Decker for questioning Leopold, he offers Decker a job as a consultant on the high school shooting case. Working with Lancaster, Decker uncovers major clues about the shooter: The killer gained access to the school through a bomb shelter connected to the abandoned army base next door.

Decker’s good work draws the attention of FBI Agent Ross Bogart. When the killer murders Bogart’s assistant, it becomes clear that the school shooting is connected to the murder of Decker’s family. The killer is trying to draw out and punish Decker for reasons unknown. Decker runs through his own inner DVR but can’t recall whom he might have offended or when.

Jamison visits Decker to apologize for the inaccurate news article. Jamison wants to help Decker find the killer because Jamison’s mentor was among the victims of the school shooting.

Leopold is released because he had an alibi for the night of the murders and for the school shooting. Decker questions Leopold at a local bar after his release, but Leopold leaves abruptly. Later, Decker finds Leopold has disappeared and becomes convinced that Leopold is working with the school shooter.

The body count grows as the killer eliminates people close to Decker and leaves taunting messages that Decker is to blame for the carnage. Clue by clue, the trail leads back to the Cognitive Research Institute: Decker realizes that the killer is a former patient and intersex teenager, Belinda Wyatt.

Wyatt was raped and beaten by a gang of police officers and football players; Wyatt classifies Decker symbolically as one of her abusers because Decker was both a football player and a cop. Leopold has been helping Wyatt carry out her revenge since the two met through a website called “Justice Denied.”

Decker stages a confrontation with Wyatt and Leopold and reveals that Leopold has been luring victims to “Justice Denied,” stealing money from them, and killing them. Leopold shoots Wyatt, and Decker wrestles Leopold to the ground before Leopold can fire another shot. Decker suffocates Leopold to death.

After the investigation is over, Bogart asks Decker and Jamison to join an FBI special task force. Jamison assures Decker that he won’t be alone ever again.