In the thrilling conclusion to the Alpha Core Trilogy, Calder McKenna and Sierra Mason are forced to face the demons that plague them and brought their team to its knees. As GenMed closes in, finding them at every turn, pushing them to run from the places and people they love, they realize once and for all that they must stand and fight or see their lives and those around them forfeit. How far can a person be pushed before instinct overpowers the one thing that drives them to kill? How long can a person hide before fear is eradicated by sheer will? For Calder and Sierra, the answer lies within the key and the key lies within them. All they need do now is find it.