Caitlyn Cook (Perrey Reeves) was a recurring villainess on the fifth and final season of Covert Affairs. She was Ryan McQuaid's assistant at McQuaid Security, and in her first appearance in the episode, "False Skorpion," she introduces herself to Arthur Campbell and goes on a dinner meeting with him. They were shown working closely together for several episodes, including being part of the action in the episode, "Embassy Row."
Caitlyn turned heel in the episode, "Sensitive Euro Man," where it was revealed that she was framing Ryan for the attacks in Chicago. She allowed the CIA to investigate Ryan, only to hide Ryan's laptop in her desk. Caitlyn met with Ryan and returned his laptop to him, only for Ryan and Annie Walker to discover that a GPS was planted in it, so his every move would be tracked. She is also revealed to be working with Georgian diplomat Aleksandre Belenko, and they planned to frame Ryan for a bomb attack at the signing of a treaty, with the bombing set to take place in the motorcade.
Ryan followed Caitlyn and confronted her inside the restroom of a nearby building, only to be shot by the traitorous villainess. The bomb is later discovered by Annie and Arthur, but Caitlyn uses her cellphone to detonate it. Later on, the evil Caitlyn engaged in a fight with Annie in a parking garage, with Caitlyn proclaiming that she "will never stop us." During the fight, Belenko arrives and shoots Caitlyn, who displays shock at his action before Belenko kills Caitlyn with a second shot.