Venus "Vee" Delmonico, played by Emma Roberts, is a high school senior residing on Staten Island. One day, she receives a Facebook notification from her crush, J.P. (Brian Marc), tagging her in one of her own photos. Shortly after, Vee gets a Skype invitation from her friend Sydney, portrayed by Emily Meade. Sydney excitedly introduces Vee to a thrilling and dangerous game known as Nerve, set to take place over the next 24 hours. The game consists of "players" who undertake daring challenges in exchange for cash, while "watchers" pay to witness the antics unfold. Despite Sydney's enthusiasm and encouragement to join her, Vee declines, largely due to her concerns about leaving her mother, Nancy (Juliette Lewis), alone after the tragic loss of her brother, a wound that still lingers for both.
At school, Vee contributes to the yearbook, primarily featuring J.P. in her photographs. When she attends a pep rally with her friends—Tommy (Miles Heizer), Liv (Kimiko Glenn), and Wes (Marc John Jefferies)—Syd seizes an opportunity to record her own dare. She provocatively moons the crowd, successfully completing the challenge. Later, during their meal together, Sydney continues to pressure Vee into joining Nerve, pointing out that Vee rarely takes risks. The situation intensifies when she approaches J.P., asking if he'd be interested in dating Vee, only for him to dismiss her, claiming she’s not his type, which sends Vee home in frustration.
In her solitude, Vee decides to create an account on Nerve, where the rules clearly state that dares must be filmed, and failure to complete them results in losing any earned money. If anyone reveals details about the game, dire consequences will follow. Deciding to step into the spotlight, she alters her course and agrees to become a player. The very moment she joins, Nerve begins to gather her private information.
Determined to dive into her first dare, Vee calls Tommy to take her to a diner where her challenge is to kiss a stranger for five seconds in return for $100. With the clock ticking, she spots a guy named Ian, played by Dave Franco, engrossed in reading To The Lighthouse, her favorite book. She kisses him while Tommy films the act, thus completing her dare. However, upon turning around, she discovers Ian has disappeared, only to later see him performing a spirited dare at the diner. Ian then dares Vee to join him in the city for $200. Hesitant at first, she throws caution to the wind and hops on his motorcycle.
Once in the city, Vee is faced with a new dare that requires her to try on a couture dress. Coincidentally, she spots Ian trying on a suit as well. However, their clothes mysteriously vanish when they return to their dressing rooms, forcing them to leave the store in nothing but their underwear, all while being filmed by their followers. They find the clothes waiting for them on Ian’s motorcycle. Just then, they meet Ty, played by Machine Gun Kelly, who hints at knowing Ian and notes their ongoing dares.
Meanwhile, Tommy decides to stakeout the diner as Vee participates in the game. He contacts his hacker friend Azhar (Samira Wiley), requesting assistance to uncover the dark underbelly of Nerve. On the other hand, Sydney, now envious of Vee’s rising follower count, engages in her own dares throughout the city with Liv and Wes.
During her adventures, Vee and Ian find themselves at a tattoo parlor where Ian designs a unique tattoo for her, reminiscing about her cherished book with a lighthouse symbol. Meanwhile, Nancy (Vee's mother) becomes aware of unexplained money transfers within their joint bank account and reaches out to Tommy, who fabricates a story about Vee's new job.
As Vee and Ian enjoy a whimsical carousel ride, Sydney, fueled by jealousy, daringly attempts a nerve-racking challenge involving a precarious ladder spanning two buildings. Unfortunately, she slips, bailing out of Nerve. Vee arrives at a party with Ian only to have Sydney confront her about past grievances, resulting in a heated argument. Vee, aiming to save face, takes on Sydney's dare, traversing the ladder effortlessly. However, when Vee attempts to reconcile, she finds Sydney in an intimate moment with J.P., revealing Ian's intention to ignite discord between the two friends.
Feeling betrayed, Vee considers reporting Nerve, but Ian intercepts her, pleading with her not to, yet her resolve remains. After alerting a cop, who dismisses her claims, disaster strikes when Nancy informs Vee that their bank account has been drained. Alone and vulnerable, Vee encounters Ty, who remorselessly knocks her unconscious.
Upon awakening, Vee finds herself trapped in a freight container, ominously marked with "SNITCHES GET STITCHES." A voice reverberates from a TV inside, threatening that since she revealed information about Nerve, they now control her fate. With only one way out—involving winning the game—Vee emerges into the world again, encountering Ian, who discloses he too fell victim to the game a year prior when a dare went horribly wrong.
As the climax approaches, Vee resolves to reconnect with her friends. Meanwhile, Ian faces a near-fatal dare: hanging from a crane with one hand. Succeeding with remarkable courage, he progresses to the final stage of the game. Vee finds herself tasked with retrieving a seemingly innocent package, only to discover it contains a loaded firearm.
The finale unfolds in an arena filled with watchers, where Vee and Ian face a heart-stopping dare: to shoot one another. Ian urges Vee to take the shot, but she refuses. Suddenly, Ty proposes to shoot one of them, rallying the crowd in a frenzy. Defiantly, Vee calls out the twisted thrill-seekers who crave bloodshed for their entertainment. In a shocking twist, Nerve places her life in the audience's hands, voting on whether she should be shot. The verdict allows Ty to pull the trigger, and Vee collapses in Ian's arms. As the chaos hammers down, the watchers' identities are exposed, and they exit the game in fear of complicity in murder.
In a brilliant twist, it’s revealed Vee orchestrated the entire sequence, having used a blank. With the dust settling, the game is shut down, and Vee and her mother recuperate their stolen money with Azhar's help. As a fresh chapter begins, Vee and Ian, whose real name is Sam, embark on a new journey together, sharing a kiss as dawn breaks on a hopeful day ahead.
