Brooke Mathison (Mariana Klaveno), also known as Claudine Poyet and Angela Lindsay, was the secondary villainess of the first season of Designated Survivor.
Born in Seoul, South Korea, Brooke Mathison (as revealed in "One Hundred Days") became a member of the True Believers, an alt-right terrorist organization founded by the season's main antagonist—Patrick Lloyd—who wanted to transform the United States into a military empire. Furthermore, four years before the series' events, she introduced herself to Chief of Staff Charles Langdon at a high-society ball as a contractor named "Claudine Poyet" after he had gone through a divorce.
Langdon fell for her instantly, and even though the latter did not reciprocate his feelings, he eventually gave her intel and information on the U.S. Capitol threat assessment. In Charles' words, Brooke was very inquisitive about the subject, and she would later use the information to help her co-conspirators orchestrate the bombing of the Capitol, which killed almost everyone present at the 2017 State of the Union, including President Robert Richmond. Langdon (who wasn't there) and Peter MacLeish were among the survivors of the attack.
It was also uncovered that the evil Brooke contacted Charles before said attack and blackmailed him into naming Thomas "Tom" Kirkman (the series' main protagonist) as the titular designated survivor, doing so because it was initially believed that he would not serve as a threat to the True Believers' plans. When Langdon attempted to escape on the night of the explosions, Brooke had her associates hack into his car, which caused him to crash into a river; he miraculously survived.
Brooke made her first official appearance in the final scenes of episode 1.07, "The Traitor." To elaborate, she informed FBI Deputy Director Jason Atwood that she and her cohorts were holding his son Luke hostage. The villainess' response to his demand for his location was to threaten to have both him and his wife Yvette killed if anything were to happen to her.
The following episode, "The Results," picked up where the scene left off, with Brooke ordering Atwood to falsely confess to the murder of Majid Nassar (the deceased leader of a terrorist group based in Algeria called Al-Sakar), which he did to save his son's life. She was also shown having a conversation with Peter, which officially confirmed him as being a conspirator aligned with the True Believers, with the reveal of the latter's wife taking place two episodes later in "The Oath."
Episode 1.12, "The End of the Beginning," had her learning of the location of FBI Agent Hannah Wells while referring to herself as "Angela Lindsay." Once she obtained that information, she contacted Peter's spouse and told her about what she had discovered. Additionally, during this episode, Luke's corpse was found on a riverbank, indicating that the former either instructed for her fellow villains to commit the murder or perpetrated the crime herself.
In the season's fifteenth episode, "One Hundred Days," Brooke attacked Hannah after she paid a visit to her address, managing to put her in a chokehold until Jason arrived and pointed a gun at her. This was followed by the terrorist attempting to provoke him into shooting her, and when that failed, she prepared to use a hidden sidearm against the two, only for both Wells and Atwood to kill the deceptive woman before she could.
- Before Brooke's name was officially revealed in "One Hundred Days," she was simply credited as "The Mysterious and Calculating Dark-Haired Woman."
- Mariana Klaveno also played Abby Reed in the 2007 film The Sitter.