Mark St. Clair's life has fallen apart: he is diagnosed with incurable cancer just as his engineering career is taking off. Thinking that his life is over, he agrees to leave his wife and young daughter to undergo a radical new technology. Now, in a secret facility in Colorado, Mark is frozen alive in a controlled death, awaiting a cure for his brain cancer. He awakes to find a bioagent has wiped out most life-forms and the Complex facility is under the watchful eye of Rex, a supercomputer capable of imitating intelligent human behavior.
The computer's algorithm calls for another person to be resuscitated every few days. As new people are revived, Rex tightens its grip, battling Mark for control of the operations and imposing even greater restrictions on the group. Mark and his allies feel trapped. Rex has killed before, and there's no stopping it now, since its devious developer has been resurrected. Now, in the wrong hands, Rex represents the greatest threat to human life.
When Mark learns the true purpose of the Complex, he decides to escape the facility and take his chances on the outside. Each survivor must now take sides. Whom can Mark count on? Who will side with the AI? Desperation spurs the allies to leave the Complex, and they nearly succeed until events take an unexpected twist.
What is really important in a world where AI has redefined life? This is a question that haunts Mark as he and his friends struggle to move forward in a barren world, as the frigid winter closes in. The stakes are nothing less than the future of humanity. If Mark can't outwit Rex, an entire civilization will vanish.