For years, a serial killer dubbed The Crypto-Killer mutilated women and left cryptic ciphers on their bodies. FBI Special Agent Callum Cooper was the one to solve the ciphers and catch the killer...Or did he? Now retired from the FBI because of a fatal diagnosis, the REAL killer emerges with a new mystery for Callum, and his past comes back to haunt him, torturing him in his last days. With the help of Aisha Miller, a bio-tech genius college student, Callum and Aisha are tasked with confronting this agent's past mistakes, as they both seek redemption before it's too late.