Pittsburgh, 1986: The city is gripped in a panic as a maniac slips poison onto pharmacy shelves. All of the evidence has pointed to Ron Corbett, but shoddy policework let Corbett off the hook, left the crime unsolved.

Ten years later, it’s happening again. This time, for the most personal of reasons, Detective Downing has made it his mission to see Corbett behind bars. He enlists the help of Jim Christensen, a psychologist who specializes in memory, to interview Corbett’s son, now a young man with a painful past and problems of his own. Does the boy remember his father poisoning pill containers? Has he blocked memories of a horrific crime spree enacted in his own house? As Christiansen explores the boy’s memory and Downing grows more obsessive investigating the case, both men fear that the killings now may not be as random as they once thought, and that unlocking memories may draw them too close to a vicious predator.