The team investigates the death of a SeaBee at a contruction site and realize that the killer stole a bunch of TNT. Tracking the shipment, they locate a hideout and discover that the TNT isn't going to be used to blow something up; it's being turned into toluene to process cocaine.
But even more surprising, they all but stumble across Percy and an extensive DEA operation. She had been working with the DEA to take down her old friend Marian, who now plays an important role in a major drug ring. Pride is angry at being left out of the loop and demands the DEA let them in from there on out.
They track the coca leaves to a flower shop, where Percy encounters Marian herself. They follow Marian back to her house, and Percy's emotions get the better of her. They take Marian in, but she refuses to cooperate at first. Percy threatens to make sure Marian's daughter ends up in the system.
Marian sets up a meet with the head honcho, but it is a trap, and Marian is shot, and the boss escapes. Tracking the boss back to his hideout, they take him down and Percy personally rescues Marian's young daughter. Percy ensures that Marian and the little girl get into Witness Protection.