After Percy convinced Amanda to release him so that he can stop Operation Clean Sweep, he holds members of Oversight hostage at Gates House. A Division bomb squad is frantically trying to deactivate all of the explosives as part of the operation.
Alex goes back inside Division to see what he can do to stop Clean Sweep.
Nikita and Michael form a once unlikely alliance with Pierce in order to rescue key members held by Percy in Gates House, particularly Pierce's mother the senator. Meanwhile, Gogol is also tracking the Guardians to Gates House.
Alex enlists help from Birkhoff to stop the Clean Sweep by disabling the controls at ground zero while Nikita, Michael and Pierce work out the details of their Oversight member rescue. Percy endeavors to try and kill his Division guards while Gogol tries to take over.
Before Nikita and team can get to Gates House, Percy orders a massacre. Senator Pierce is the only survivor. Gogol manages to take down one of the Guardians, but Nikita, Michael, and Pierce shot a number of Gogol's hit men.
Among the survivors of this bloodbath are Percy, a Guardian named Miller, and Roan. Alex and Birkhoff manage to save Division from complete annihilation.
Thankful for her rescue, the Senator promises Nikita and Michael a Presidential pardon. The mystery person Amanda has been contacting recently turns out to be Ari, Semak's right-hand man. With most of the members of Oversight dead, Amanda has a lot of room to maneuver.