Troy Gable, a recent law school dropout portrayed by Colin Hanks, finds himself amidst the bustling life of Los Angeles, desperately searching for a job to kickstart his career. His journey takes an interesting turn when he stumbles upon an advertisement for a personal assistant position. That fateful day, he sets off to a local restaurant for an interview where he meets the enigmatic Great Buck Howard, played by John Malkovich. Although initially skeptical of Buck, who is a fading mentalist with a flair for the dramatic, Troy is drawn in by the promise of adventure and excitement far removed from his mundane existence. Hesitantly, he takes on the role and joins Buck on his journey across the country, performing in half-full venues in small towns where Buck’s charm still manages to leave a lasting impression on the local crowds.
While Buck may have a prickly personality and his tricks seem straightforward, it is clear that this is where he thrives. One of his signature acts involves hiding his performance fee in the audience while he waits backstage, only to return and effortlessly identify it from the crowd with unerring accuracy.
As Troy immerses himself in this world of magic and illusion, strife brews at home. His father, played by the legendary Tom Hanks, discovers that his son is no longer enrolled in law school and instead is playing the role of an assistant to a mentalist. The confrontation is heated, leading Troy to consider abandoning Buck for his father's approval. However, Buck urges him to stay a bit longer, promising a "spectacular" trick that aims to be the climax of his career.
As they prepare for a big event in Cincinnati, Buck enlists the help of a New York PR firm, but is disappointed when a junior publicist named Valerie, portrayed by Emily Blunt, is assigned to him. Although Buck remains dismissive, a spark develops between Valerie and Troy, culminating in a night spent together. On the day of Buck’s anticipated performance, Valerie impresses Buck with her ability to gather media attention; however, disaster strikes when important news breaks about a local celebrity, causing reporters to abandon Buck just as he attempts to set a world record by putting an entire room full of participants to sleep.
Buck’s fury escalates when he later learns that a magazine article, which was supposed to celebrate his work, instead paints him as a "has-been" and a fraud. Troy, sensing Buck’s despair, rushes after the now-upset Valerie, but their conversation is interrupted by a shocking turn of events: Buck collapses from the stress and frustration of the situation.
In the hospital, Buck confesses to Troy that he feels his career may be at an end, yet unexpectedly, news of his trick manages to spread across local channels, igniting a newfound interest in Buck’s career. Once again he finds himself a hot topic, gracing the covers of magazines and appearing on talk shows, yet when he is unexpectedly dropped from a coveted spot on "The Tonight Show," Buck decides to take his act to Las Vegas. This new Vegas, however, is vastly different from what he had once known, demanding a flashier approach that leaves him feeling out of place and nervous.
During his highly-anticipated debut, everything appears to be in place until Buck’s signature trick falters; he is unable to locate the hidden money. Just like that, the fleeting opportunity for a comeback vanishes, and Buck disappears from the scene. Troy returns to Los Angeles, where Valerie offers him a chance to work as a writer's assistant on a television show. Despite the great opportunity, a hollow feeling remains as he misses Buck’s unique presence.
One day, Troy finds an announcement for Buck’s performance at a community arts center and decides to reconnect by attending. In Buck's dressing room, he questions Buck about a rumored accomplice for his tricks and the mysterious events in Vegas. Buck reveals that the glitz of Vegas was not what he desired; he misses connecting with small communities where his act can resonate. As Buck commands the stage once more, Troy experiences a wave of nostalgia for the genuine energy of Buck’s act.
Watching from the audience, Troy is captivated once again. When Buck reveals a surprise for the crowd, the setting feels right; the intimacy and shared laughter resonate deeply. Buck calls for volunteers to examine him, setting the stage for his signature act, which involves the audience and their participation. With a touch of nervous energy, Buck steps through the audience once more, finally honing in on a gentleman who initially protests but ultimately reveals the hidden cash Buck has been searching for. With triumphant brilliance, Buck proves yet again that he has not lost his touch, receiving the adoration of the audience that he cherishes the most.
