A courtroom frenzy ensues and sweeps 1970s America when a young single mother reluctantly tips the attention of a widespread manhunt toward her longtime boyfriend, Ted Bundy.
Notorious serial killer Ted Bundy starts a relationship with single mother Liz Kendall. After he is arrested and put on trial for his alleged crimes, Liz tries to support him, but the case takes a toll on her and drives her to drink.
Ted escapes custody twice and kills a number of women. He finds support from other young women who are attracted to him and think he is innocent, including Carole Ann Boone, with whom he fathers a child. Ted is later found guilty on all charges and is sentenced to death by the electric chair.
On the day of his execution, Ted is visited by Liz one last time so she can get closure. He quietly confesses to one murder before she leaves him. Bundy was executed in January 1989. Liz and her daughter still live in Washington and she is now sober, while Carole Ann gave birth to Ted’s daughter.
1969 – Single mother Elizabeth Kendall (Lily Collins) is at a college bar with her friend Joanna (Angela Sarafyan). She meets a charming stranger by the name of Theodore Robert Bundy (Zac Efron). He puts a quarter in the jukebox to play “Crimson and Clover” so that the two may share their first dance. Liz goes home with Ted where they sleep together platonically. In the morning, Liz wakes up and sees Ted isn’t next to her, and she can’t find her daughter Molly until she walks into the kitchen to find Ted making breakfast with Molly sitting near him.
As footage of Ted and Liz being together and raising Molly plays, we hear a news report on a series of grisly murders involving numerous female victims. Witnesses identified the suspect as a man faking a broken arm in a cast who lured women in Lake Sammamish to his car asking for help loading a boat onto his car. A sketch has also been released of a man looking like Ted.
Utah, 1975 – Ted is pulled over by a police officer and is promptly arrested. He is being named as a suspect in an attempted kidnapping of a woman named Carol DaRonch (Grace Victoria Cox). Ted gets a lawyer, John O’Connell (Jeffrey Donovan), who gets his bail reduced so he can be back with Liz soon. When he does see Liz again, she is angry with him for his arrest. He tells her that someone had given the cops his name in Utah that led to his arrest. Ted also sees a black car that has been following him since he got back. He later goes to a library and is kicked out after a patron recognizes Ted from the newspaper, after which he spots the black car outside driving off as Ted approaches it.
Just before the kidnapping trial, O’Connell brings up the disappearance of the women at Lake Sammamish and how his name ended up on the suspect list. DaRonch later identifies Ted as the man who tried to kidnap her, but O’Connell tries to defend him by insinuating that she was set up to frame Ted. However, Ted is later found guilty of the kidnapping and is remanded to Utah State Prison. Liz is devastated by the verdict, but Ted assures her he will prove his innocence.
Upon arrival at the prison in March 1976, Ted is harassed by other inmates since he committed crimes against women. He is being investigated by Detective Mike Fisher (Terry Kinney), who wants answers from Ted and also contacts Liz regarding the case. While she wants to believe Ted is innocent, the stress of the case starts to take a toll on her, and she begins to drink. Even O’Connell gives up on being Ted’s lawyer as things get worse. The more Ted starts to contact Liz, the more fed up she gets. She starts finding comfort with friend and coworker Jerry Thompson (Haley Joel Osment).
Ted is soon on trial for the murder of Caryn Campbell. He is held without bail while the death penalty is being sought against him. His new lawyer, Jim Dumas (Justin McCombs), thinks this is just circumstantial. Ted starts to plan an escape while reporters start to interview him while he is in prison. During a trial recess, Ted spots an opportunity as the guard watching him is talking to a young woman, so he uses it as a chance to jump out the window to escape. He changes clothes in the streets and walks off before authorities proceed to hunt him down. Liz hears news about this with Joanna, but she tells Liz that Ted will most likely not seek shelter with her. Ted is then caught and captured once again. Liz goes to visit him just to tell him that she can’t keep supporting him as his case only gets worse. She leaves him with a drawing that Molly made for him.
Ted later escapes prison once again by cutting a hole through a ceiling. He ends up in Florida two weeks later where he meets two sorority girls, both of whom are later murdered before other female students are reported to have been attacked in their sleep with a heavy wooden log. Ted is pulled over by a police officer, but Ted hits the cop and runs away before he is soon recaptured. Sherriff Ken Katsaris (Kevin McClatchy) promises to make sure Ted is put away for a long time. He forcibly has pictures of his teeth taken as he has a chip in the front, which matches a bite mark on one of the victims. As the media draws attention to Ted’s case, he earns a number of female fans because of how handsome he is, which also leads them to think he really is innocent. Among them is an old friend of Ted’s named Carole Ann Boone (Kaya Scodelario), who moves to Florida to be closer to him.
Ted gets a public defender, Dan Dowd (Brian Geraghty), while prosecutor Larry Simpson (Jim Parsons) tries to find evidence to convict Ted. Dowd tells Ted that the state is offering him a deal wherein he would plead guilty to killing the sorority girls and get life sentences instead of the death penalty. Ted refuses to take it.
The trial against Ted begins with Judge Edward T. Cowart (John Malkovich) overseeing the trial. Ted is apparently allowed to defend himself during the trial, attempting to sway public opinion toward him while denying the evidence against him, though his behavior makes Dowd quit on him. He grows closer to Carole Ann, but she thinks he still loves Liz. Liz, meanwhile, admits to Jerry that it was her who gave Ted’s name to the police in Utah. During one trial hearing, Ted proposes to Carole Ann, who accepts, and they are legally married in the courthouse. She later becomes pregnant with his child.
The jury then makes their final verdict. Ted is found guilty on all charges. Cowart sentences him to death via the electric chair. Carole Ann, Liz, and Ted’s mother are all gutted by the sentence. Ted firmly maintains his innocence.
Ten years later, Liz receives a final letter from Ted as he is set to be executed. She goes to visit him in prison to ask him to tell her the truth, since she can no longer bear the pain of not knowing. Ted still insists that he didn’t kill anybody until Liz pulls out a picture she received from Fisher of one of the victims, a woman who was found decapitated. Liz asks Ted what happens to her, and he writes on the glass between them, “HACKSAW”. A flashback shows Ted luring the woman to his car with the fake cast before bludgeoning her with a crowbar, and then taking her in the woods to dismember her. Liz leaves and quietly cries on her way out, thinking back to her time with Ted and realizing there were signs of his instability from the very beginning. She goes outside where she reunites with Jerry and a now teenage Molly, who tells her mom she is proud of her for finally getting her closure.
The final text reads that Ted Bundy was executed on January 24th, 1989. He confessed to over 30 murders, but experts believe he killed many more. He had requested that his ashes be scattered in the Cascade Mountains where he buried some of his victims. Liz and Molly Kendall still live in Washington State, and Liz has been sober for decades. Carole Ann Boone gave birth to Ted’s daughter Rose while he was on death row. A list is also shown of Bundy’s known victims.
Footage of Bundy’s trial is shown, as well as pictures of him with Liz and a number of people cheering for his execution.