The unit's Field Team of operatives finds themselves facing new challenges when both their old nemesis, UniPerp, and a new one arrive on the scene at the same time. How will the team handle Hank's revelation regarding UniPerp? Can they taunt him into coming forward and being caught the same way he has been taunting them? Or will he continue to elude them? And what about the new threat: a man who communicates through what appears to be an unbreakable code? Just what is he trying to reveal? Included in this book is a reader challenge: Can YOU break the code? Also included is Anne Fox's take on the identity of Zodiac—an unsolved case still on the FBI's books.