Erica (Zoey Deutch) gives a police officer a blowjob in his car while her two friends catch them in the act on video. They then extort him for money as Erica is not eighteen. It is revealed that she and her friends extort ephebophiles frequently as a form of vigilantism. Erica totals up her earnings, which she is saving up in order to bail her father out of prison.
Her mom’s new boyfriend Bob has a son, Luke, who gets out of rehab and comes to live with them. Erica and Luke soon develop an unlikely friendship.
While at the bowling alley together, Luke has a panic attack when he sees his middle school teacher, Will Jordan (Adam Scott), who he accused of sexual assault. Will was never charged due to inconsistencies in Luke’s story. Later that night, Erica interrupts Luke’s suicide attempt.
Erica and her posse decide to make Will their next target, with Luke reluctantly participating. At the grocery store, Erica flirts with Will, who is aware she is a teenager in high school. Later, she approaches him at the bowling alley, and they make out in his car in the parking lot. Before it can go any further, she abruptly stops it. Her friends accuse her of sabotaging the plan because she likes him.
The gang forms a new plan and they lace a beer with roofies. They accidentally pour in too much, so Erica says she won’t let him drink the whole thing. Erica arrives at Will’s house with the six pack, apologizes for the other night, and they go inside his house to hang out. Erica asks about the miniature Eiffel Tower replica on Will’s coffee table, which was a gift from his ex-wife. This prompts Will to tell her about how he was accused of molesting Luke, which he vehemently denies. Although he was never charged, he tells her how the accusation ruined his life. Erica realizes he’s almost done with the beer, so she slaps it out of his hand, and he feels the strong effect of the roofies. He grabs her arm, and Luke runs in and punches him, causing Will to fall backwards onto the coffee table, smashing it. The four of them pick Will up and prop him up on the couch while two of the girls strip down to their underwear and take pictures with him to use to blackmail him. Luke worries that his breathing is too slow, but they leave, shaken by the encounter. On the way out, Erica sees that the other girls vandalized his garage by spray-painting the word “pedophile” on it.
The next morning, the cops show up at their house and accuse Erica and Luke of vandalism. When they mention that they haven’t been able to get ahold of him yet, Erica and Luke go back to the house to make sure he’s okay. When they arrive, Will is sitting limp on the couch exactly where they left him. They try to shake him awake and he falls over, revealing the Eiffel Tower impaled in his back and a puddle of blood. Luke convinces Erica they have to run away to Mexico.
While on the run, Erica throws up from guilt, and looks for reassurance from Luke that Will deserved what happened to him. Luke reveals that he was never molested by Will; he walked in on Will molesting his classmate and lied to protect her and other possible victims.
Luke surprises Erica by driving her to her dad’s prison and giving her bail money. However, she is heartbroken to find out that he was bailed out a few days ago and did not contact her.
Erica decides she doesn’t want to live her life on the run, and she wants to go home and turn themselves in. Luke agrees, but on their way back, a police car sirens them to pull over. Erica tells Luke that they can’t get caught before turning themselves in, so they try to lose the police on a dirt road. In the chaos, Luke confesses his love to her. They give up on the chase to stop to have sex and are found by police as they lay together on the ground.
One month later, Erica visits Luke in prison, shortly before her house arrest begins. Despite their circumstances, they are happy and in love.