Owen drops in on Nikita and Michael sharing a bed, and while things are awkward, he explains that he's there to get Nikita's help to obtain a black box he's traced to London. Nikita agrees, but because she suspects Owen is acting very oddly, she asks Michael to help keep an eye on Owen in case he goes berserk. Luckily for Michael, Percy is sending him to help protect that self-same black box in London. Nikita and Owen find the black box guardian's storage unit, but the place is booby-trapped.
They manage an escape before the unit is destroyed. Nikita discovers that Owen is acting strangely because he's in withdrawal. Division had made him a drug addict and without the pills supplied by his former bosses, he's going a little stir-crazy. The pair track down the guardian and a foot chase ensues, with Owen eventually managing to take down the guardian and toss him into the Thames.
Unfortunately, the black box will only open with a sample of the guardian's blood. With the guardian now gone, the pair have to put together a plan to lure him back. Owen contacts Percy, and Division sends a strike team (including the guardian) to nab him. By the time Nikita and Michael arrive at the same location, Owen has taken down the entire team and gotten a sample of the guardian's blood.
He plans on uploading the information on the box to the internet, but Nikita wants the box outright destroyed. Michael ends up shooting the box, completely destroying it. With the box gone, no one has reason to fight, and they all part. Meanwhile, Amanda is growing suspicious of Alex's loyalties so she gives the young agent a lie detector test. Unfortunately, Alex initially fails the test, but she manages to partially pass it later, blaming her anxiety on her complex relationship with Thom. Amanda seems to accept that as the truth, but later she marks Alex for cancellation. However, Percy refuses to put out the order, and Alex is safe, for now.
During the gunfight in London, the filming is obvious to have been in Canada for several reasons: the cars are driving with French license plates, the cars in the background are driving on the right ride of the road, and there are yellow lines down the center of the road and none at the sides of the road. The UK has white dashed lines in the center of most roads and double yellow lines (or red lines in London) at the sides to indicate no parking.