- "My host's identity was fiction. The product of a character-building exercise in social media, and which, in her case, was our primary source of information. In reality, Marcy is a mentally-challenged woman living in the care of the state."
- ―Marcy Warton
Marcy Warton (Traveler 3569), played by starring cast member MacKenzie Porter, is the medic for the show's core team. The host body is a mentally disabled woman who works as a cleaning girl in a library. The fact that she was mentally disabled was unknown to The Director and others in the future due to fake social media profiles created as an exercise with her social worker David Mailer to help teach her about the world. The fake social profile stated she was a librarian and David was a reporter she had met while he was doing research for a newspaper story.
Marcy was to have died at the hands of a group of hooligans as shown in the opening scene in the first episode, Travelers. In the scene, Marcy distracted the group from terrorizing a colleague who had just left work and as the group started to come for her, she fell on a staircase and bumped her head, knocking her unconscious. When she awoke and didn't see the group, she started to leave only to be met by the group who then started assaulting her. The consciousness transfer occurred and Traveler 3569, being trained in hand-to-hand combat, was able to beat them off in spectacular fashion. The fight was recorded by CCTV which was seen by Police Officer Jeff Conniker, the estranged father of fellow traveler teammate Carly Shannon's child, who begins looking into Marcy.
3569 Future History
At some point, traveler 3569 went through medical training as well as training for the traveler program.
She was separated from her brother when they were young and only remembers that her brother had night terrors, which led her to believe that Luca may be her long-lost brother.
Prior to working as a cleaner, Marcy lived in a ward in a hospital which was known for being abusive towards its residents right up until its closure. (Travelers)
It's later revealed that rather than having lived there her entire life, she'd worked there with Vincent Ingram who had offered her a kind of scam for some money. She took up this offer and regretted it as soon as she saw the machine, but she was physically forced to go through with the procedure. It caused memory loss and brain damage which ended in her becoming a resident there, now having developmental issues.
Sometime later, presumably around the time the ward closed, Marcy was abandoned. She was taken to a street full of homeless people. As she wondered around, she bumped into David who helped her. He looked after her as a social worker, getting her a part time job as a library cleaner and a small, subsidized apartment. He also visited her on a regular basis. It's clear Marcy liked David and wanted him to be her boyfriend, though he said that was inappropriate.
David also revealed that the hospital she'd been living in had no record of her ever being a resident there. This is probably the reason why the Director wasn't aware of mental disability. (21C)
Traveler 3569 (First Version)
Traveler 3569 was transferred into Marcy's body on the same night as the rest of the team, apart from Grant MacLaren. She defended herself against the attackers who were historically supposed to kill the host. She then walked home.
In the morning, David comes to visit her and she answers the door naked. After getting dressed, David takes her to the doctor due to the cut on her head and the fall from the previous night. On the bus ride to the doctor's office, David said that it's 'reading out-loud day' and begins to pull out a children's book but Marcy reads an article in the newspaper instead.
She waited outside the doctor's office while David and the doctor argued over whether her increased intelligence was a medical miracle or the result of Marcy forgetting that she was pretending to have intellectual disabilities. When she repeated the story she'd been taught in the future, about being a librarian and meeting David doing research in the library where they met, she was told that it was all a lie for a social media experiment. She then has a seizure and ends up in the hospital, though she walks out as soon as David leaves. She ends up staying at David's.
She goes to the abandoned building where she meets her team in the 21st century for the first time and helps to explain to Grant, the host, what they are in the moments before he dies. She also helps to stop Jonas Walker's shooting rampage. (Travelers)
Marcy goes back to David's after completing the mission. He wants her to go to the doctor but she refuses saying she is one and explaining what happened to her. He gives her a phone and she leaves to meet with Philip, finding that the team leader they're supposed to meet died of an overdose within seconds of arrival.
Later, she noticed Philip sweating, and later shaking, and realises that his host was a heroin addict, not a one time user as their death certificate showed. She later confronts him about it, as well as the fact that her host was in fact mentally disabled and her whole social media was fictional, and tells him to continue taking heroin in small, controlled doses. (Protocol 6)
Traveler 3569 (Second Version)
Because of the host's mental disability, Marcy knew that she was going to continue having seizures and die fairly soon. Traveler 0027 (Grace Day) said that she would be able to reboot Marcy's consciousness, which would allow her to continue living but would also remove some of her memories, including all the ones she'd created as Marcy. Marcy debated going through with it and wanted to at least talk to David before she went through with it. However, Grace Day tricked her into performing the reboot before she was able to talk to David. Her team briefed her on what had happened, but knew that she wasn't the same. (Marcy)
Marcy goes to some trouble to try to remember what she'd forgotten when she was overwritten. She connects herself to a monitor and bathes in a bath of ice attempting to bring herself to the edge of death since almost dying caused Grant to witness his host's memories. Here, she begins to remember what happened when host Marcy was still alive: how she worked in the hospital ward with Vincent Ingram and where Simon was also a patient; how she was forced to use the machine which caused her brain damage; how she became a patient in an abusive hospital where Vincent would give her “treatment”; and how she was eventually abandoned, which lead to her bumping into David on the street who began looking after her. She also remembered small parts of her relationship with David pre-reboot. The ice bath caused her to have a seizure which Carly rescued her from. (21C)
Version Two (Host)
After the timeline is reset Marcy (host) is seen on the back of a bus talking to David. It's implied that the Director got the message from Traveler 3468 (Grant MacLaren) and so didn't sent 001 to Twin Towers just before 9/11 (confirmed a few couple of minutes later when a message from the Director appears on the screen saying that the transfer of 001 failed -implying a misfire or a stopped attempt), which then meant that he was never able to get Simon to set up the machine which would have caused brain damage in Marcy, giving her the intellectual disabilities.
Instead, she's seen on her way to work at a new hospital because she didn't like the way the last place she was at (the mental hospital where Simon was a resident) treated their patients.