Plot - based on Showcase recap - a work in progress
Marcy is an intellectually disabled woman who has a job as a cleaner. In the opening scene, she sees a female coworker being attacked by four violent men in the dark parking lot outside the library where she works. When Marcy hears the screams of her friend, she bangs on the glass windows of the library which turns the gang's attention towards her instead. As her coworker runs in the opposite direction, leaving her bag on the ground, and the gang focus on Marcy instead; Marcy sprints up the stairs, trips and hits her forehead against the concrete.
Later, she ventures outside, thinking the gang has left, but when she bends down to pick up her colleague's bag, they attack her and she falls to the wet pavement.
On the ground, she grabs hold of her head and cries out in horror and pain. Eventually her screams vanish and she opens her eyes with a different look in her eyes. She stands confidently and demands that the men return a possession that her friend David gave to her. Her voice sounds different; she does not stutter now. The men laugh at her, and she pummels them.
The next time we see Marcy, she's lying awake in bed. She hears a knock at the door accompanied by a man's friendly voice saying her name. She asks if that's "David?" and he replies "Yup!". When she opens the door, David is shocked to see that Marcy is completely nude; he asks Marcy to get dressed and takes her to the doctor about the cut on her forehead.
To pass the time on the bus, he suggests they do some reading out loud. He reaches into his bag to grab a kid's book but as he does so Marcy begins to read on her own from a newspaper, easily, with no stuttering or difficulty understanding it. He stares back at her in confusion. When they arrive at the doctor, David asks him what is going on with Marcy. The doctor says that nothing can be going on. Marcy has a severe intellectual disability and he promises that no injury could increase her intellectual capacity to this level. When they quiz Marcy about the details of her life she says that she works as a librarian and that David is a reporter who often checks out books from her. David patiently corrects her. She is not a librarian. She cleans the library and he is not a reporter. He is her social worker. She got the mistaken ideas from a fake social media profile that she and David wrote together as a learning exercise.
Marcy nods, acknowledging her mistake, has a seizure and loses consciousness. The next time we see her she is lying in bed once more but this time in a hospital. Marcy realizes that her host body has a good deal of pre-existing damage and that she is at a diminished capacity. She insists that she can't be in the hospital because she has important work to do. "At the library?" David asks. When he goes to fetch the doctor she makes a run for it and heads straight to her social worker's house, David's house. When he returns he wants answers, but she doesn't provide any. She sleeps on David's couch, naked again. When David leaves to go to work, Marcy informs him that she's going out later and that he should stay in because the streets won't be safe. He wants to know what is going on, but Marcy shuts him up with a kiss. He accepts this answer and exits. Whilst he's going out, she's already using his computer.
Trevor is a high school quarterback who is taking a break from football to do some kickboxing. We join him in the middle of a losing fight with his skin bruised, his muscles weak and his mouth full of blood. His friend tells him to concede the fight from outside the cage. Trevor doesn’t listen, returns to the match and within seconds he is hit again and collapses. Like Marcy, he holds his head and screams as his consciousness is overwritten by a traveler. He stands up and politely concedes the fight.
Trevor, now completely different, wakes up early in the morning because he heard birds chirping, and sits in his family kitchen attempting to decipher an "R U Ok Babe?" text from his girlfriend. His Dad tells him off for putting a sports scholarship at risk by getting involved in the fight and his sweet mom gives him an apple. When he replies "Thank you, Mom" his Dad is amazed "Thank you, Mom? Who the hell is that?"
Trevor's girlfriend, Rene, doesn’t wait for a response to her text. She jogs up to his house, hugs him tightly and wants to have sex with him. He says no thanks and tells her that due to brain damage, from the fight, he doesn't know who he is and needs her assistance to make him remember. Rene agrees to help. He has a similar conversation with his friend at school when he doesn't know which locker is his. His friend shows him which locker belongs to him, and is puzzled to see Trevor at school at all.
Philip, the third traveler, has a host who is a drug addict and a college student. He's taking heroin with a friend, Stephen, when his consciousness is overwritten. When the the transfer is complete, he watches his friend die, throws away the syringe, puts on his jacket and leaves.
As Philip sits hunched over a computer at an internet cafe, typing apparently jumbled numbers and reading the word "Confirmed," he is approached by a police detective who tells him about his friend's death. Phillip isn't surprised, so the detective is suspicious and brings him in for questioning. Phillip tells the truth, but he's going through withdrawal, so he's a tad disoriented.
The detective comments on Phillip's addiction, says he knows everything there is to know about his life and speculates that Philip injected his friend with heroin, which would make his friend's death manslaughter. Later, his understanding lawyer, Ray, says he struggles with an addiction himself. He claims it’s cigarettes, but Phillip guesses correctly that it's gambling.
Ray wants to him to plead guilty, but Philip uses the attorney-client confidentiality agreement and his legal counsel's gambling addiction to his advantage. He provides his lawyer with a cash advance and the guaranteed outcomes of a horse race. His lawyer wins a lot of money and gets him released.
Philip refuses to provide his lawyer with any more guaranteed horse racing outcomes. When Phillip's legal counsel is no longer his counsel, the drinking detective returns and chases Phillip around town for a while, but then has a heart attack and dies, as Philip watches and cries.
Carly is a single mom in an abusive relationship with a man named Jeff. She is taking care of baby on her own and having to defend herself against the violence of the father of her child. We witness this struggle in her first scene when she is attempting to warm up food for her child. Jeff, drunk, pressures her to let him in. She opens the door and Jeff wonders what the "shit" on the table is. She tells him it's baby food and he knocks her to the ground. Carly screams in agony as her traveler arrives and Jeff gets even angrier and more violent in response. When her consciousness has vanished, Carly is completely different and forces Jeff to leave.
Carly searches the internet for "how to care for an infant" as she gently feeds her baby cookies. Like the other travelers, she logs into the traveler database and investigates the status of her colleagues. When she also sees the word "Confirmed" she turns to her kiddo and whispers that "Daddy is coming". This is obviously not a reference to Jeff. When his car pulls up to her house again she is not happy to see him and does not accept his apology. Carly educates him on the difference between a fight and abuse, limits when he can see his son and warns him about paying child support. When he wants to make it up to her, she says he can change the baby’s diaper.
Jeff does not back down. He begins to stalk Carly; he parks outside her house and watches her from a distance. He drives alongside her as she walks down the sidewalk and gets jealous when she speaks to any man. He demands to know where she is going. When he aggressively approaches her though she does not tolerate his intimidation. She does not have time for him and when he yells that she has to "make time" she defends herself and knocks him to the ground.
The fifth and final traveler is Grant MacLaren. He is a FBI Special Agent and the traveler team's leader. He becomes involved with the travelers when a coworker of his is sent a "red flag" for suspicious online encryption communication. Grant takes a look at the traveler's database and admits that he has no idea what he is looking at. The code and jumbled numbers and random words are unlike anything he has seen before. His fellow FBI agent (and partner) thinks the users might just be gamers but he did find GPS coordinates that correspond to an abandoned building downtown. Grant is preoccupied with arresting a potential shooter named Jonas Walker, but takes on the case and begins investigating.
He is intrigued when he learns that the IP addresses connected to the encrypted communication are oddly scattered throughout town. He becomes more intrigued when he discovers that the man who set up the chat room (Philip) was arrested and then released on a technicality. Grant decides to contact Philip's arresting officer and visit the owners of every IP address. He speaks with Trevor's mother but thinks little of the interaction because she concurs that her son is a big time gamer. Grant calls the detective who informs the agent that Philip strangely just won some money which Grant takes note of. But, the detective assures him that there is no way Philip is associated with a terrorist organization. Grant drops in at Carly’s place he inquiries if she will be going out that evening because he suspects that the travelers are planing to gather in the abandoned building later that day.
Carly does have plans, but she lies to Grant. When Grant swings by David’s home, Marcy doesn’t answer the door so he calls David, who fails to mention that a changed Marcy has been staying with him. He does mention though that maybe his neighbours who use his wifi were responsible for the IP address. Grant isn’t too panicked about the situation until he tries to reach out to the detective again and is told that he recently passed away. This is enough to motivate him to check out the abandoned building, gun in hand. Jeff was on Carly’s tail and strolls through the space too as he calls out her name. When a blackout sweeps the city, Grant almost falls to his death through an open elevator shaft from the 12th floor.
Trevor steps in and saves him from falling. Marcy, Carly and Philip step forward from the shadows and explain that they have been waiting for him, and that they are on a mission from the future. They do this while counting down to Grant's death and while Grant notices a lifeless man on the ground. They continue their explaining and identify the body as Jonas Walker, the shooter that Grant failed to arrest. The travelers took the matter into their own hands and stopped Walker from going on his shooting rampage. Before Grant can arrest these vigilantes, his knees buckle, he grabs his head and screams in pain. His consciousness has been replaced by a traveler and his first words are "I see we all made it. Let's begin."