Sam, working in deep cover with the terrorists, manages to get word to Tom Ryan that three cars, loaded with dirty bombs, are being dispatched to unknown locations. With this limited information, the Unit works to locate and neutralize those cars. When they do, they learn that they're all decoys and Sam is with the actual dirty car bomb in Washington. They desfuse the bomb and bring the terrorists to justice. The episode ends with a special Unit wedding between Grey and his newfound love Joss.