Four brilliant investigators combine forces to outwit an insidious master of online mind control in a gripping thriller by the Wall Street Journal bestselling author of The Final Equinox.

Investigator Sloan McPherson finds a frightened vagrant suffering from amnesia living in a Florida swamp-then learns he disappeared from Oregon when he was a teenager. To find out how he ended up three thousand miles from home thirty years later, Sloan enlists the help of two brilliant colleagues.

FBI agent Jessica Blackwood and scientist Theo Cray have already made an alarming connection. A female classmate of the Everglades drifter disappeared at the same time, and their high school journals reveal ties to an enigmatic figure they both called Mr. Whisper. Under his influence they did as they were told. The case is also attracting the attention of corporate security expert Brad Trasker, whose trail is leading to the dark heart of a master manipulator.

Jessica, Theo, Sloan, and Brad must now bring their unique skills to the table to take down a diabolical adversary. Unless Mr. Whisper's decades-long control of the vulnerable is too powerful and far-reaching to stop.