Joe Gunther and his team at the Vermont Bureau of Investigation (VBI) are faced with the most complex and deadly case of their careers when they are called in to investigate a series of violent deaths that appear unrelated to each other. However, the crime scenes were staged and, despite initial appearances, those deaths are, in fact, murders. And the clue that provides the link between them all - a single drop of unexplained blood at each crime scene, coming from three additional unknown people - leave the police with more questions than answers.

From old fashioned police work to the very cutting edge of forensic techonology, Gunther uses every possible investigative method in his elusive search to find the common thread before the next body shows up.