It seems that Washington was only a frontman for a rather large weapons smuggling operation. The BATF is keeping him at a safe-house out in the country, but Washington's boss now wants him eliminated. Rally and May go to see Washington at his request, and Washington is trying to get their help. Apparently there is a leak in the BATF, and Washington knows his life is in danger.
Nastajja Radinov, a female ex-KGB agent, is hired to tie up all the loose ends... which means getting rid of Washington, Rally, May, and Bill Collins. While Radinov is on her way to pay Washington a visit, she almost runs Rally and May, who are just leaving, off the road. Once at the safe-house, a fairly graphic gunfight ensues. When it's over, five BATF agents and Washington are dead.
Back at their place Rally, May, and Becky are trying to figure out the significance of the two items Washington slipped into May's back pocket as they were leaving the safe-house: a note, containing an address and phone number, and a Rolex watch that Washington asked them to deliver to his daughter. Bill and another BATF agent are outside in their van again, listening in on the conversation.
When Rally teasingly takes May's soda away, May falls over on the couch while reaching to get it back. Once on the floor, however, she notices a little extra appliance plugged into a corner outlet.
They realize it's a bug, and so they have Becky personally deliver their leftover pizza to the guys outside. After a brief exchange, Bill drives away, but not before May had slipped under the van and gave them a little parting gift... about a block down the road, the underside of the van explodes leaving Bill, the other BATF agent, and all their equipment tossed around the inside.
Rally, May, and Becky figure out that the information Washington gave them is actually a way to access information via a web page that Rally saw Washington looking at when she was trying to buy guns from him (for the BATF sting operation - chapter one). They retrieve a list of weapons, sources, and locations, and then head off to a warehouse where some of the goods are being stored.
Rally and May find a crate full of guns, but they are caught by five thugs and another gunfight takes place. May slips out the side, and Rally takes the direct route -- right through the thugs. Just after Rally drops the last one, Radinov is about to get Rally with a spring loaded knife from her perch atop a nearby stack of barrels. But, a gunshot to Radinov's cuff (she wears a bullet proof coat) throws her aim and she misses. Bill, who had also bugged Rally's computer, had the same weapons and location list, and so he showed up on the scene in time to save her.
May slipped out the side, but gets caught by Radinov in the process. The police are on the way, and so Radinov just grabs May and takes off in her car. Becky is alert to this and she brings Rally's Shelby Cobra GT 500 around to pick up Rally and give chase to Radinov.
The movie ends with a dramatic car chase, which has some of the best action sequences in the series, and of course May's escape.