In a last ditch effort to find help and a cure, Alan and Julia go to an abandoned satellite station discover a shocking secret that reveals Hatake's ultimate goal and the reason why he has developed the deadly virus.

The Vectors start working together to hunt down the uninfected as the CDC develops a risky cure and a band of assassins from Ilaria secretly infiltrate the base.

Peter and Jordan leave the safety of the Abbey to retrieve some specimens and discover just what’s living in the woods, meanwhile Sister Amy plots to make them leave forever.

As Michael struggles to keep the abbey under control, the CDC team moves closer toward tracking the source of the pathogen. Alan fights the urge to rejoin his team and confronts the reality about Peter’s allegiances. In the future, Walker makes a desperate attempt to escape from her delusional father, with potentially deadly consequences.

Alan, Kyle and Winger search the woods for the tree with red sap that might be a cure for the pathogen.

The Abbey becomes a house of horrors as Kyle struggles with his infection and Anne begins to shape a successor to Michael.