A former medical detective for the Centers for Disease Control, Dr. Nate McCormick had seen enough suffering to last a lifetime. Now he’s left the CDC, determined to begin a new life with his girlfriend in San Francisco…until the vicious murder of a biotech researcher—an old friend—hurtles him back into the medical world he’d left behind. While the police hunt for a killer, Nate starts sifting through evidence, determined to find what his friend did to provoke his brutal death. And the truth he ultimately discovers far exceeds the very worst he had imagined.