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.

After warning Kelly to leave the city with Zack ahead of the spreading plague, Eph is arrested by the FBI. Eichhorst has one final job for Gus, while Setrakian realizes that the coming eclipse is the tipping point for virus infection and the beginning of the end.

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.