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 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.

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.