With Nora gone, Eph reluctantly joins Setrakian's quest in hopes of gathering enough evidence to warrant a citywide quarantine. Fet encounters the unexpected inside the subway tunnels, and a medical emergency threatens Palmer's master plan.

Setrakian, Eph, and Nora formulate a plan to track down the Master using Jim as bait. Eichhorst and Setrakian’s pasts are revealed. At the Luss home, Neeva struggles to protect the children while encountering a mysterious stranger whose help she may not want.

Eph races to safeguard his family, only to learn that Kelly is missing. Dutch reveals her role in Palmer’s plan, and Gus is forced to make a difficult decision about Felix.

Dutch returns with a plan to broadcast Eph’s warning about the vampiric plague. However, they face a new threat when Eichhorst launches his own attack against the pawn shop. Palmer receives a special visitor, and Gus gears up for the on-coming fight but discovers there’s another mysterious factor involved.

Eph and Nora experiment on their newfound patients. Fet and Dutch grow closer as they clear out the neighborhood buildings, and Kelly begins her hunt for Zack.

Eph and Nora finally see their lethal virus in action. Fet takes the security of Red Hook into his own hands while Dutch and Setrakian set off for Staten Island to question Fitzwilliam, Palmer's former body guard.

New information from the Lumen forces Setrakian to seek help from his lifelong nemesis, Eldritch Palmer. Eph's new experiments to understand strigoi communication seemingly take him to the brink of madness while Fet is on a mission to discover strigoi movements across New York City.