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.

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.

Eph investigates Kelly’s disappearance and struggles with what he finds. Dutch pursues a plan to retaliate against Palmer, and Fitzwilliam makes a surprising choice.

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 work on a biological weapon to kill the strigoi, and Setrakian risks the lives of the entire group to find information about a closely guarded secret text. The Master begins the next phase of his own plan, by creating a terrifying new breed of creature and placing them under the control of Kelly.

Gus and Vaun wage an attack on Palmer as Eph struggles to connect with Zack. Councilwoman Justine Faraldo vows to bring her extermination policies to the other boroughs.

Eph concocts a plan to make and distribute a bioweapon. Gus realizes Angel can be an unlikely ally, and Kelly comes after Nora and Zack.

Setrakian and Fet use Fitzwilliam's info to attack the Master. Eph returns to NYC frustrated but energized to go after the one person responsible for killing his friends.

Eph and Dutch work together to thwart the Master's greatest ally. Justine runs into trouble with the Mayor while Setrakian tracks down the real owner of the Lumen.

Dutch fights for her life against Eichhorst as Fet, Nora, and Eph frantically search the city for her. Setrakian confronts an old acquaintance on his search for the Occido Lumen, while Gus helps the Guptas escape across the border to safety.