Fourteen-year-old Jason Shepherd is a chronic liar who lives in Michigan. After pulling off a big lie to avoid summer school for failing English, he finally completes a creative writing assignment that could save his grade. But fate intervenes: on his way to turn it in, he collides with a limousine carrying Hollywood producer Marty Wolf. Jason accidentally leaves his essay in the car, and Wolf discovers it. Seeing potential, Wolf decides to use Jason's story for his own benefit without giving Jason credit. When Jason realizes his work has been stolen and transformed into a blockbuster movie, he tries to tell his parents and the police but no one believes him due to his past dishonesty.

Determined to prove he's telling the truth and to reclaim his story, Jason and his best friend Kaylee fly to Los Angeles during spring break to confront Wolf. Once in Hollywood, they embark on a series of comedic and adventurous schemes to force Wolf to admit the truth. Their plans become increasingly elaborate, but Wolf proves to be a tough adversary who is as deceitful as Jason used to be. The young duo must navigate through the challenges of the movie industry, build unexpected alliances, and grow in the process, all while staying one step ahead of Wolf's attempts to foil them.