Sera has always relied on her intuition, even if she never quite understood it, and when she dreams of a girl trapped in a tank, suffering, she knows she has to help. With a little digging, she uncovers the fact that the Valley's origins might not have been as benign as she thought. In fact, her parents, who she thought were renowned scientists fighting the infection, might have been part of the very project that released the infection into the world: the Scorpio Project.
Sera is determined to follow the clues in search of the mysterious girl. They lead her to the Plum Island Animal Research facility, and a shadowy figure called Scorpio. In the course of her discovery she finds there is a new, deadly virus, one created by Vise as a fail-safe, but Sera isn't sure if Scorpio is fighting the virus or fanning it. With enemies inside the facility, Sera must learn to rely on reason over instinct if she is to survive.