Before Season 5Edit
After Vaughn was captured, Curtis slipped Vaughn a package with a secret code hidden inside a battery. Curtis demanded to know where a man named James Lehman was, but Vaughn said he didn't know so his bodyguard began to pin his dislocated arm to the table. Curtis fooled Vaughn into revealing that the code was an secret message and demanded a pencil. Vaughn asked for Curtis to snap his arm back into place and just as his bodyguard did so, he attacked him and escaped.
During a meeting at a train yard between James Lehman and Michael Vaughn, Dean and Curtis showed up and ambushed the meeting. While Dean shot Lehman in the back, Curtis took out a submachine gun and riddled Vaughn with bullets to the chest. (Prophet 5)
After his death, Curtis went to Amsterdam to attend an arms deal with a man named Heinrich Roemer. When Curtis got his package, a case containing Nuridium, he betrayed Roemer and shot him in the chest, departing with the vial. Unfortunately, while walking away, he was captured by Sydney and Dixon. During the interrogation, Sydney demanded to know the whereabouts of Dean and Prophet 5's intentions, but Curtis denied everything. Even when Sydney offered immunity, he didn't accept it, fearful of what Prophet 5 would do. Curtis continued to deny everything until Sydney kicked him out of a window and into the water, where he escaped. Before she did, Marcus fooled him into drinking water that had a tracking system inside of it.
APO later discovered that Curtis was on a plane headed for Pyongyang and stealthily boarded the jet to track down Curtis and his package. Curtis encountered Sydney again, but found her with a knife on the tube supplying the Nuridium to the package. Curtis couldn't kill her without risking damage to the package, so the two fought briefly until Curtis was subdued by Sydney. Curtis told Sydney that no matter what they did, he'd be dead by nightfall for his failure. Knowing he would die at the hands of Prophet 5, Curtis intentionally opened the door to the plane and was sucked out, falling to his death. (...1...)