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Warning: Contains plot spoilers

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Warning: Contains plot spoilers

Having survived the bomb at the market but forced to flee again, Stephen, Yasim and Michael take refuge in the "swamp." Michael is now getting ill, as a result of taking the tainted vaccine. Nye and Turney, who still have Michael under surveillance, watch with interest.

Russell, however, is not out of the game yet. He goes after Nye, breaking into his house and copying his laptop's hard drive.

Watching Yasim and Stephen together, Michael works out the true nature of the bond between them and confronts them. Yasim can't bear it and leaves, but while she's collecting her thoughts in a café, she is approached by Russell. He reveals that he's been making progress, and that it was him who abducted Cooper.

Russell takes Yasim, Stephen and Michael to his new hideout and brings Cooper to them while Stephen gets to work on decrypting Nye's laptop. Cooper agrees to help, but needs samples of other infected blood to compare against Michael's. Russell knows where the refugees who arrived with Michael are being held, and Stephen volunteers to break in and get samples.

As Stephen holds the hands of the dying refugees while extracting their blood, he has a revelation more explosive than he could ever have imagined. Stephen's world is turned upside down as he realizes that not everyone is who they seem, and he has been skillfully manipulated in an intricately constructed cover-up. The race is now on to expose the truth before all evidence is destroyed — including those closest to him.