Former Army officer Shepherd and his team of private contractors are sent into a former Soviet bio-weapons lab to extract a rogue scientist but their mission takes an unexpected and terrifying turn.
Shepherd and team try to figure out what they're dealing with, tensions grow between Kirk and Emily and Meknikov wants answers from Sambuco.
The squad finds Pavel - he and Tariq learn about the experiments, Brooks gets separated from the squad and faces a precarious situation with Anna and Gabriella.
Shepherd and Kirk duke it out and Kirk goes off on his own then Tariq and Pavel find Dr. Damen and take him into custody. Meknikov hires a spy.
Meknikov's hired gun gets into Sambuco's lair and sees Pavel is in danger, Tariq takes a stand against opening the doors, and a dire situation awaits Thompson.
Shepherd's taking it hard after losing Thompson, Sambuco orders a hit on Meknikov, who goes into hiding and the squad embarks on a zombie hunt.
Brooks has a "date" with Gabriella. Tariq stands in Shepherd's path and pays dearly. Anna confronts Dr Damen and questions his real motives.
Anna and Pavel pledge to help Damen with finding a cure while everyone else is committed to getting out, and Tariq makes the ultimate sacrifice.
Kirk finds the ventilation shaft he sought - and so does Meknikov; Sambuco's plan C messes with the minds of Shepherd and the others; Emily tries to blast open a door.
Kirk must get Meknikov to the ventilation shaft!
A Zombie breaks loose. All hell follows it.
Shepherd's former comrade mysteriously appears just when the team thinks they can get out.
When Subari arrives with backup, the squad scrambles to take the cure and make it out of the underground alive.
