A troubled Baltimore FBI agent becomes involved with a secret government unit assembled to hunt a group of ruthless terrorists, who may or may not be from this world, and who may or may not be involved in his wife's disappearance.

Flynn and the ETU take a look into some unhappy attacks on American soil, and find out that the Hunters are working with human collaborators.

After a succumbing to a particularly nasty Hunter urge, young Regan learns the truth about what she is from her father ... and his knife.

McCarthy is captured as Flynn's search for his wife leads to desperate actions. Plus: Get ready for a Hunter birth!.

Flynn stumbles upon startling new information about his wife, which leads the ETU to a suspected human-hunter collaborator, while Flynn finds himself in an unexpected confrontation.

The ETU's discovery of the name and suspected location of a High Value Target, dredges up old memories for Jackson. Meanwhile, Flynn, Regan and Briggs attempt a daring raid on a Turkish prison.

The Hunters attempt to "reprogram" a captive Regan. While the ETU work to locate their missing agent, they deal with the possibility that there could be a mole in their ranks.

While Regan reunites with a long-lost family member, Flynn self-destructs and Abby makes a bold move.

Abby's loyalty is tested, Flynn hits rock bottom and Regan must bargain one of the family member's fate for another's freedom.

Flynn's past become dangerously present while Emme's investigation into Abby puts her own life at risk.

The ETU sets up an elaborate plan to halt The Purge, but how far will Regan and Flynn go to spare innocent lives?.

Fugitives Flynn and Regan make a dangerous play as help for the ETU comes from the unlikeliest of sources.

It's the day of The Purge and the fate of the human race lies in the ETU's hands.