A deadly virus forces humanity to run unusual genetic experiments with animal DNA.In a dark future, Doctor Mercy Perching has received a terrifying message. The FossilFlu virus which drove humanity to the brink of extinction, has mutated and threatens a second pandemic. Along with the message is a mysterious personal invitation to visit the Sanctuary of Americas, one of the last three cities left on Earth. When Mercy arrives, she is shocked to discover that the Sanctuary of Americas has been engineering human-animal hybrids to be immune to the virus.Drawn into a dangerous internal war, where the cure to the virus is the key to power and the fate of the hybrids, Mercy's research may have the answers. But who will she save?