Dr Ephraim Goodweather and his team investigate a plane that lands in New York City with everyone on board dead. Pawnbroker Abraham Setrakian is convinced that something sinister is beginning.

The four survivors begin manifesting strange symptoms, but Eph and Nora's attempt to quarantine them is thwarted. Setrakian receives a surprise visit from an old acquaintance.

Eph and Nora fight to save Captain Redfern's life before coming face-to-face with the horrifying effects of the virus.

A secret autopsy demonstrates the bizarre progression of the mystery virus; Eph and Nora race to find the father of the youngest victim of the plane tragedy; Ansel takes desperate measures to protect his family.

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. A medical emergency threatens Palmer's master plan.

It's the beginning of the end as Setrakian realises that the upcoming eclipse is the apex for viral infection. Meanwhile, Eph is arrested after warning Kelly to leave with Zack before the plague spreads. Eichhorst has one last job for Gus.