The four survivors begin manifesting strange symptoms, but Eph and Nora's attempt to quarantine them is thwarted as the disinformation campaign begins. Meanwhile, in jail, Setrakian receives a surprise visit from an old - a very old - acquaintance.

A secret autopsy demonstrates the bizarre progression of the mystery virus, prompting Jim to make a startling confession. Eph and Nora race to find the father of the youngest victim of the plane tragedy, but someone unexpected beats them to it. Ansel, in the grip of disease, takes desperate measures to protect his family.

Eph and Fet recon for an all-out assault that Setrakian assures them will finally kill the Master. Gus aligns himself with a strange new force, one that may swing the fight in an unforeseen direction.