The Maze Runner
In the film adaptation of The Maze Runner, Teresa arrives in the Glade sometime after Thomas arrived. Since the Box appears to be out of schedule, the boys gather, and Newt jumps down into the Box to see what this is about. Teresa is delivered unconscious, making Newt comment: "It's a girl. I think she's dead." But she briefly wakes up until she sees Thomas, saying his name. Then she goes back to sleep for some time. Later, Jeff and Clint run into the Map Room and tell Thomas and Minho that Teresa is awake. Thomas, Minho, Jeff, and Clint run to Chuck, who points up to Teresa, who is now hiding on the platform, shouting and throwing stones at the boys to keep them away. Only Thomas is allowed to go up and speak with her. They wonder why they are different.
Soon after that, Alby, having stung by a Griever, wakes up to the Changing. He starts fighting, but Teresa suddenly remembers she had two syringes with a serum with her when she arrived in the Glade. She injects one of them into Alby's chest and he instantly calms down.
Next, there's a commotion because the doors didn't close for the night. Without much time for the Gladers to prepare, the Grievers enter the Glade and kill many of the boys. One Griever attacks Chuck, but Alby saves the younger boy by hacking off the stinging limb. One moment later, Alby gets caught by the same Griever and dies. Thomas uses the stinging device to stab himself in the thigh to regain some memories that might help them escape the Maze.
In the next morning, Gally, having taken command after the Griever attack, has Teresa and Thomas tied to poles right at a door, as an offering for the Grievers. But his plan fails, Teresa and Thomas get free and convince most of the Gladers to come with them to finally escape, while Gally chooses to stay in the Glade. While the others fight against the Grievers, Teresa punches in the code and successfully opens the exit. The surviving Gladers find themselves in the WCKD headquarters where they receive a video message from Dr. Ava Paige. They are about to leave when Gally, having been stung by a Griever, appears with a gun, insisting that they will never be free. He fires a bullet at Thomas, but Chuck sacrifices by taking the bullet in the chest, giving Minho a chance to throw a spear at Gally, causing it to non-fatally impale him in the chest, causing Gally to drop to his knees, drop the gun, and collapse on his right side on the floor. Teresa watches Chuck die in Thomas' arms before being taken along with the surviving Gladers to a helicopter by a group of masked soldiers.
The Scorch Trials
In the film adaptation of The Scorch Trials, contrary to the books, Teresa is almost the whole time with the boys, from their escape from WCKD to the camp of the Right Arm.In the beginning, all of the surviving Gladers are brought to a WCKD facility that is buzzing with activity. They can take a shower and get medically tested. During these tests, Teresa gets separated from the boys, sedated and tubed. Sometime later, Thomas and his new friend Aris persuade the others to escape from WCKD. They rescue Teresa and get out.Together, they hide from the search patrols and helicopters. They find an abandoned mall where they stock up clothing and nutrition but also awake their first Cranks. Two boys of their group die, but most of them manage to escape. Winston receives a nasty scratch at his belly, thus he gets infected with the Flare. He gets weaker as they proceed through a desert and finally collapses. He reveals his wound to the others and asks them to end it. Newt hands him a pistol, and each of them takes their leave from their comrade, who shoots himself with the pistol.
Sometime after when they pass the night without shelter in the desert, a heavy storm builds up and they make it just in time to the first building of a ruined city. When they turn on the lights, chained-up Cranks reach out for them, screaming. A short-haired tough girl comes to take them to the boss, with Brenda presenting the group to Jorge. He wonders how their arrival could be his advantage and has them hanged up by their feet until they tell him everything. In an unattended moment, they manage to free themselves. But then, WCKD forces storm the place in search of the fugitives. Teresa and most of their group escape with Jorge, but Thomas and Brenda get separated and have to find their way as the building explodes.
They find and rescue Thomas and Brenda, who have been drugged out on a party by Marcus, who was supposed to assist them but had switched sides and is now meant to sell them to WCKD. Jorge forces the man to tell them where they can find the Right Arm. The group goes to the mountains in Marcus' car.
They have to stop at a roadblock, and when they get out of the car, they immediately get shot at by unseen people. None of them gets injured, though, and finally, two girls (Sonya and Harriet from Group B, who now work for the Right Arm) round them up and threaten them with their guns. They recognize Aris, saying they were in the same Maze together. They take all of them to their leader, Vince.
Finally, everyone seems to enjoy the peace of the moment. With the Gladers and Group B each relaxing with their peers, Teresa seeks solitude on a mountain. Thomas follows her and she tells him about her parents, her Crank father is finally past the Gone, her mother is infected, too. She tells him about her resolution to find a cure and her infinite trust in WCKD. At this moment, WCKD bergs show up in the sky, and Thomas concludes that Teresa has called them.
After a desperate fight, the Right Arm is defeated and WCKD has them all kneel in lines. Teresa stands at the side of Chancellor Paige with a sad face. She had hoped that Thomas would see reason, understand, and support her. Nearly all captives are brought into the berg, including Minho, Aris, and Sonya. Teresa enters the berg along with the WCKD personnel (Paige, Janson). Thomas announces that he will find and rescue Minho and kill Paige. Vince and the remaining group agree.
The Death Cure
In the film adaptation of The Death Cure, Teresa is working as a scientist for WCKD. She is seen in a white lab coat searching for the cure.
Minho is being tortured, with sensors measuring his killzone activity. Teresa never intervenes, no matter what Minho suffers. She then goes to see a little infected girl named Cheyenne, injecting her with the content of a syringe. Teresa hopes that she has finally found the cure. Cheyenne gets better. Dr. Paige watches them from the corridor through a window. They are talking and laughing.
Teresa tries to talk to Minho, but he shows no reaction at all. He seems to be broken. When Teresa is about to end the meeting, Minho attacks her, screaming at her for being a traitor. The guards restrain him. Teresa, still shocked by that incident, walks along the corridor when Dr. Paige finds her and urges her to come and see Cheyenne. She has gotten worse than ever before, almost fully Crank.
When Teresa leaves the WCKD Tower, she suddenly recognizes Thomas on the other side of the street. She follows him into an alley and they talk. Teresa is happy to see him. Thomas asks her if she is sorry for what she has done to them. She replies that she is, but she would do it again because she thinks it is the right thing to do. From behind, Gally appears and puts a sack over her head. Thomas and Gally take Teresa to an abandoned church where Newt, Frypan, Brenda, and Jorge are. Teresa is shocked to see that Gally is alive, and he asks her where Minho is. Teresa replies that Minho is in Sub-Level 3 with the Immune children. Gally takes a scalpel and tries to use it to cut off Teresa's finger, but Thomas stops him by taking the scalpel from him. Thomas convinces Teresa to remove their trackers.
While removing Thomas' tracker, Teresa notices that Brenda is looking good and healthy, and asks Thomas when her last treatment was. Thomas replies that Brenda's last treatment was back in the mountain camp of The Right Arm. Teresa removes Thomas' tracker. Gally approaches Teresa and Thomas and asks them if everything is okay. Thomas replies that it is. Teresa tries to pick up a scalpel from the table but Gally stops her and takes her outside, though not before Teresa grabs a cloth with Thomas' blood on it from the table.
Teresa, along with Thomas, Newt, and Gally, go to the WCKD Tower, while Frypan climbs up a crane, Brenda goes to a parking lot to steal a bus, and Jorge returns to the Right Arm's hideout. Teresa, Thomas, Newt, and Gally arrive in a stairwell. While Thomas talks to Frypan and Brenda on a walkie-talkie and Gally plugs a jamming device into an electrical box, Teresa watches as Newt starts coughing due to being infected by The Flare.
Teresa, Thomas, Newt, and Gally arrive in Sub-Level 3 where Thomas, Newt, and Gally shoot the WCKD guards. Thomas discovers that Minho is not in the cell and asks Teresa where he is. Teresa shows Thomas Minho's profile and tells him that he has been moved up to the medical wing. Teresa, Thomas, and Newt go to find Minho while Gally steals the vials of serum from the vault and takes them and the Immune children to Brenda.
Teresa, Thomas, and Newt take the elevator to find Minho. Janson joins them in the elevator and talks to Teresa, but then realizes that Thomas and Newt are there. However, the trio manages to escape. When Thomas asks when the Trials at WCKD will stop, Teresa insists that it will when they finds a cure. Thomas furiously retorts that there is no cure. Janson holds them at gunpoint, but Teresa manages to let Thomas and Newt go to find Minho while she goes to do a blood test on Thomas' blood.
Teresa examines Thomas' blood and finds that it not only keeps the Flare virus in check, but also destroys it. She reveals this to Ava Paige, then suggests that they find Thomas.
While Thomas is dragging Newt to the berg, Teresa broadcasts her voice throughout the Last City, telling Thomas that his blood can cure Newt like it did Brenda and that he needs to return to WCKD.
After Thomas mercy-kills Newt, he enters the WCKD Tower and talks to Ava Paige. Paige tells Thomas that he can save them, but is shot in the back by Janson, who takes Thomas to a lab where Teresa is extracting his blood. Janson reveals to Thomas that he has been infected by the Flare and plans to inject the serum with Thomas' blood into his arm and only those he deems worthy. Teresa then turns against Jansen and hits him in the head with a glass flask, knocking him unconscious. She tries to release Thomas, but Janson regains consciousness and knocks her down. Thomas frees himself and engages Janson in a fight, but Janson overpowers him and prepares to shoot him, when Lawrence's crew fires a missile at the WCKD Tower, knocking Teresa, Thomas, and Janson down. Teresa carries Thomas to the medical wing, but not before Janson shoots Thomas in the stomach. Teresa offers to give Janson the serum containing Thomas' blood, but Janson refuses and wants Thomas himself. Thomas throws a very heavy object at a glass front, allowing the Cranks that are locked inside it to break out and attack Janson.
Teresa carries Thomas to the roof, gives him the curing serum containing his blood, and kisses him. Minho, Gally, Frypan, Brenda, Jorge, Vince, and the Immune children arrive in a Berg. Thomas is unable to board due to his injury, but Teresa throws him onto the berg, allowing Minho, Gally, Frypan, Brenda, and Vince to pull him aboard. Teresa falls to her death when the WCKD Tower collapses.
Sometime later at the Safe Haven, Teresa's name was engraved on the Memorial Rock by Thomas.
