In the opening scene, Hope Ann Greggory (Melissa Rauch) snorts some allergy medicine in a room filled with trophies and then watches a VHS tape of her competing at the Rome Summer Olympics 12 years earlier. After falling, she ruptures her Achilles heel but still finishes her routine, earning her a third-place bronze medal. Wearing the medal, Hope begins to masturbate to this footage of herself. Her father Stan (Gary Cole) calls to tell her dinner's ready but she screams at him. She is established as a foul-mouthed woman with an Ohioan accent who perpetually wears her Team USA jacket.
Hope heads out, first stopping by the mail truck her father drives for a living. She opens a handful of birthday cards and steals the cash inside. Her first stop is Sbarro Pizza at the mall's food court, where she orders a Mountain Dew (the employee asks if she wants Diet like most women but she rudely tells him she didn't say Diet). When she is charged $9.30 for the meal, the owner comes by and points out that she's on the wall -- where an autographed picture of her is hanging. Thus her meals are always on the house. Hope is revealed to be a major celebrity in her small town of Amherst, Ohio, with the city sign even boasting that "Bronze Medalist Hope Ann Gregory" lives there. This special treatment carries over to the local soda shop she often eats at, complete with her own reserved parking spot. While drinking a milkshake, a young gymnast, named Maggie Townsend (Haley Lu Richardson), and the gym manager named Ben (Thomas Middleditch) spot Hope through the window. Maggie does an impressive routine outside the window and then enters, gushing about how she's a big fan of Hope's. Hope recognizes Ben as being "Twitchy", a kid she used to torment over his facial tic, which he still has; he seems to have always had a crush on her. Maggie tells Hope she's a gymnast training with the same coach and that Hope has been an inspiration to her since her father died at five years old. Hope replies by bragging that her mother died when she was a baby.
When Hope returns home, her dad politely tells her she can't steal from his mail truck anymore. Stan tells her she should get a job coaching gymnastics and she points out that she was currently on "Dancing with the Stars" and is a star, not a coach. Nonetheless, he suggests retracting her weekly allowance. She balks at this, complaining that she needs that $700 a week to get by. They settle down with him holding a DAD'S GREATEST DAD mug that she made for him in grade school. They watch television in which it's revealed that the coach who trained Hope to the Olympics has killed herself. Hope is nonchalant in response to this, saying she hates the coach.
The next day, Hope goes to meet her drug dealer to score some weed. She tries to steal from her dad's mail truck again but it now has a lock on it. After she gets the hook-up, she comes home to learn that her father has received a letter, stipulating that in her former coach's will, Hope was left half a million dollars, on the condition she coach Maggie to the Olympic games, regardless of how she places. Hope reads the letter and tells him it says $500,000, not half a million. Yet she decides to take up the offer. She stops by Maggie's trailer home and meets her mom (Cecily Strong) and tries to convince her to let her train Maggie. They both agree, excitedly, as they are fans of hers. Maggie points out she needs a ride to the gym because she is too young to drive. She says she usually gets there by 7:00 AM but Hope promises to pick her up around noon.
Their first training session, Hope goes out of her way to sabotage Maggie's chances of success. She encourages her to binge on junk food, pointing out that male athletes do the same thing in other sports. A boy flirts with Maggie and instead of telling her not to get distracted, Hope demands that Maggie be intimate with him. When they arrive at the gym, Ben/Twitchy is there. Hope says she's going to give her a new routine even though Maggie already has one she's been working on with her former coach. She asks Maggie if she knows what the strongest part of her has to be to win -- Maggie guesses mental constitution but Hope corrects her, "Your mind," which is the same thing. Instead of actually running through the routine, Hope encourages her to lay down and visualize her performing it; she never runs through the actual routine.
The next day, they have to get to the gym early because a committee member is going to arrive to evaluate Maggie. Hope blends some weed into a green smoothie she's making for Maggie and then decides to throw in the whole bag. She tells Maggie that she must drink the whole thing. When they arrive at the studio, Maggie's eyes are bloodshot and she runs around the gym, completely high. Ben is disappointed and questions whether Hope is the best coach for her. Lance Tucker (Sebastian Stan) arrives; he is an equally conceded gymnast-turned-coach who won gold and silver at the Olympics and bickers with Hope. He took her virginity right after she won the bronze medal and they are now sworn enemies. Hope decides to quit her training and calls her dad at home, asking if she'll still get the money if she doesn't finish the task. She is told the conditions explicitly state that she has to succeed or she gets nothing. Because of this, Hope decides to change her tune -- she finds Maggie and her mom at home, talking to Stan who tries to encourage Maggie's mom to let him coach instead. Surprisingly, Maggie and her mom decide to stick with Hope.
Hope tries a different approach -- she encourages Maggie to stop kissing the boy she initially told her to. She puts her on a strict diet but tells her to sniff Hope's nachos before eating her celery stick, a trick she knew from her own gymnastics days. She gives Maggie pointers on how to do a cutesy routine to impress the judges. And how to stick a landing.
Impressed, Ben begins to like the new Hope and the two decide to go out on a date. He takes her to the mall food court from before but after hours, using a kiosk selling candles to spark a mood. They play Truth or Dare and she dares him to steal a punch card from one of the restaurants -- and then to punch them out so she gets a free meal. Eventually the game gets more serious where she talks about how crushed she was when she finished rehabilitating from her broken leg and was told by her now deceased coach that she was a has-been and her career is over.
Maggie makes it into the nationals in Toronto, Canada and everyone gears up to attend except Maggie's mom who has to stay home and work. Ben and Hope continue getting closer and Lance is there, too. An interviewer asks Hope if she is coaching because she is no longer a star and Hope gets upset. She later admits to Ben that she's afraid that if Maggie succeeds, she won't be the city's local celebrity anymore. He tells her he thinks it's great that she's coaching Maggie especially since the gymnastics studio isn't going to be around much longer because of money problems. He suspects that this is why the studio's owner killed herself because she was going through hardships financially and was broke. Hope now realizes that she doesn't have $500,000 to pay her.
Hope finds her dad in her hotel room and demands to know if the letter was real. Stan finally admits that he falsified the document to encourage Hope to get a job and make something of herself. She is angry with him but for the first time, he stands up to her, calling her a "spoiled bitch".
Upset, Hope gets drunk in at a bar and Lance begins to flirt with her. Back in her motel room, they have a hot five-minute sex session, which includes them doing gymnastics moves in the fully in the nude (i.e., he does moves on her like she's a pommel horse; she does a front flip into a handstand and they 69). It ends with her holding onto rings while he bangs her against the window. Ben is in the parking lot and sees this happening.
The next day, Ben is livid with her and tells her he saw her having sex. He wants nothing to do with her, which crushes Hope. Lance admits that he's always hated her and he had sex with her so he could ruin her relationship with Ben. He wants to take Maggie to the Olympics and steal Hope's small town celebrity away from her.
Maggie is about to perform her routine. Hope sees Maggie's mom high in the stands; she asks Hope to tell Maggie she's there. Hope finds Maggie ready to perform for the judges; she begins to tell her 'Your mom--" and stops. Maggie asks, "What about my mom?" Hope replies: "She won't be here because she was killed in a plane crash." Maggie begins to cry and when she goes to perform, she can't do it as she's too upset.
However.... this is all just a fantasy in Hope's mind -- she tells Maggie the truth that her mom is there as a surprise, which makes Maggie smile. She gives a great performance and goes on to win a gold medal, allowing her to move on to the Olympics.
Back in Amherst, the town now changes the sign to "Home of Maggie Townsend, gold medalist" and a smaller sign, "and Hope Ann Greggory, bronze medalist." Everything Hope feared has come true. At the local soda shop, Hope watches on TV as Maggie holds a press conference, telling her she couldn't have done it without her coach, Hope Ann Greggory... but then adds that being a gold medalist is going to be much more effective on her path to Olympics and announces she'll be moving to Los Angeles and trained by Lance instead. The soda shop owner calls Maggie a bitch and Hope acts somber. Hope then walks out after paying for her milkshake.
At the local mall, kids are lined up to get an autograph from Maggie who is a no show because she has moved out of town. Hope stands on the table and gives a speech to the kids using foul language but encouraging them to join the local gymnastics studio.
Ben shows up to the gymnasium, which is slated to close, but instead finds a swarm of girls and their moms outside. Hope is selling them gym clothes and T-shirts and says she won't be granting any change; all profits will go to keeping the studio around.
In the final scene set several months later, the gymnasium is still open and Hope is now the official coach in town teaching gymnastics to young girls. The city changes the sign back to simply "home of bronze medalist Hope Ann Greggory." But Hope isn't that great of a coach. During a lunch break, an ice cream truck comes by and Hope sends all the athletes outside to get some for themselves.
In a post write subtitle sequence, we're told that Maggie didn't win a gold medal at the next Summer Olympics, and had to quit gymnastics after having Lance's baby. Also, that none of the girls that Hope trained at her new gym ever went on to win a medal at any event.