Marianne Taylor

Marianne Taylor was an intelligence agent for CTU who was found to be working with Habib Marwan's terrorist cell in Day 4.

Before Day 4
Taylor was hired by Henry Powell to infiltrate the inner workings of CTU Los Angeles and cover his tracks in case it became necessary. She dealt solely with Powell and never learned the names of the people he was working for, although she did meet Forbes, who worked at the Rockland Building where Powell’s office was located. Powell had stored a list of his superiors’ names in a file on his computer, in case either he or Marianne needed a bargaining chip. In addition to a password, Powell’s or Marianne’s thumbprint would be needed to access the file.

Marianne had had a relationship with Curtis Manning. Curtis broke it off when he realized she was using him to get ahead in her career.

Day 4
On the day of James Heller’s attempted execution and the subsequent nuclear meltdown, After Heller was kidnapped, CTU called in several consultants, but because of their history, Curtis crossed Marianne’s name off the list. Marianne called CTU director Erin Driscoll and revealed that Curtis had given her classified details about the UVX system. Not wanting to go through a security reboot and ensuing investigation, Driscoll gave her access to CTU, much to Curtis’ chagrin. When Marianne arrived, she was introduced to analysts Sarah Gavin, Chloe O'Brian, and Edgar Stiles, and learned that former agent Jack Bauer was following one of the terrorists to Heller’s possible location. However, Jack was working against Driscoll’s orders. Marianne did her work without raising suspicion, although Curtis kept a close eye on her.

Marianne overheard a conversation between Chloe and Edgar, and found out that Chloe was helping Jack, and that she needed Edgar to reposition a satellite for Jack. Later, after Chloe got caught and detained, Marianne revealed to Edgar that she had heard the conversation, and threatened to report him to Driscoll unless he did what she said. She blackmailed Edgar into giving her special clearance; she thought she might as well use her leverage to get ahead. After the execution was stopped, Jack, Heller, and Audrey Raines arrived at CTU, along with the empty Override briefcase. Marianne eavesdropped on a teleconference between Driscoll and McLennan-Forster, in which they learned about the Override. She then alerted Powell that they knew.

Marianne played along with the rest of CTU in the investigation of the Override. Jack left with Audrey to go look at surveillance footage at Felsted Security, and Marianne told Powell. Once Jack and Audrey were dead, there would be an internal investigation of CTU, so Marianne had to frame somebody else. She did so by planting a digital voice recording in Sarah’s system. Sarah was taken into custody and interrogated. Jack and Audrey survived the attack, and Marianne wanted to get out of there, but Powell ordered her to stay until he could take care of things. Edgar was able to intercept Marianne’s computer and find out that she planted the recording. Edgar went to tell Driscoll, and Marianne tried to leave the building. A lockdown was enforced, but she got out. Curtis and Meredith Atterson caught her before she could get to her car and ordered another agent to impound the car. However, somebody had rigged her car with a bomb, which killed the agent when he put the key in.

Later, Marianne was put in an interrogation room, where she learned that the people behind the meltdown had killed Powell, and they were after her as well. Curtis struck up a deal with her: if she helped CTU find the Override, they would protect her. In this case, protection meant being sent to prison, but Marianne thought it was better than death, and agreed to help. The only way she knew to help CTU was the file at Powell’s office. Heller assigned Curtis to escort Marianne to the Rockland Building and retrieve the data. They arrived at the building with two guards and entered Powell’s office. Marianne used her thumbprint to log in. However, before they could enter the file, Forbes and his men broke in and killed the CTU guards. Marianne insisted that the file was still secure.She was then shot twice and killed by one of Forbe's men.