Tessa was a beautiful but troubled woman, who had been in contact with Mac about a murder she claimed to witness, but her information was too cryptic and Mac could never determine an actual murder had taken place. But now Tess has shown up dead of what appears to be of a drug overdose, but the CSI's quickly determine the OD was staged and Tessa was murdered. Using the memories of Mac's meetings with Tessa and the clues she left behind, Mac is determined to solve not only Tessa's murder but also the one he now believes she witnessed. Little does he know, he is dealing with people so powerful, they will stop at nothing to keep their secrets hidden.