FBI super-profiler Agent Meredeth Connelly begins her hunt for The .40 Caliber Killer. She collects evidence. He collects families. Her headaches become more unbearable with each crime scene, with each dead child.
With two decades of experience, she knows serial killers. As the body count rises, it's clear that this serial killer knows her. She doesn't remember him. He'll never forget her. As the investigation progresses, something awakens within her that hints at an answer.
Dreams?
Hallucinations?
Memories?
She doesn't know which. But if she can't get it under control, she'll never catch The .40 Caliber Killer.