Cold Vengeance is the eleventh book in the Agent Pendergast series and Book Two of the Helen Trilogy. It was published by Grand Central Publishing and released on August 2, 2011. It debuted at the top of the New York Times Best Seller list on August 21, 2011, the first of the sixteen Preston-Child collaborative novels to reach #1.
Devastated by the discovery that his wife, Helen, was murdered, Special Agent Pendergast must have retribution. But revenge is not simple. As he stalks his wife's betrayers—a chase that takes him from the wild moors of Scotland to the bustling streets of New York City and the darkest bayous of Louisiana—he is also forced to dig further into Helen's past. And he is stunned to learn that Helen may have been a collaborator in her own murder.-Publisher's synopsis
Peeling back the layers of deception, Pendergast realizes that the conspiracy is deeper, goes back generations, and is more monstrous than he could have ever imagined--and everything he's believed, everything he's trusted, everything he's understood... may be a horrific lie.