Jimmy Woods, portrayed by Luke Edwards, is a young boy grappling with an undefined yet profound mental disorder that has taken root since the tragic drowning of his twin sister, Jennifer, in the Green River two years ago. Struggling to cope with his immense grief, Jimmy rarely engages with others; instead, he isolates himself, spending countless hours constructing elaborate structures from blocks or boxes. His fixation on heading to "California" emerges as a prominent theme, becoming nearly his only verbal expression since the heartbreaking incident. The weight of the trauma, coupled with Jimmy's psychological struggles, has torn his family apart. He resides with his mother, Christine Bateman, and his stepfather while his brothers, Corey, played by Fred Savage, and Nick, played by Christian Slater, live with their father, Sam.
When Jimmy is placed in an institution due to his condition, Corey takes matters into his own hands, orchestrating a daring escape to flee with his brother to California. Meanwhile, Christine and her husband enlist the help of Putnam, a morally ambiguous child bounty hunter portrayed by Will Seltzer. With hopes of retrieving only Jimmy, Putnam finds himself in competition with Sam and Nick. This rivalry escalates, leading to chaotic encounters as both parties attempt to outmaneuver one another in their quest to find the boys.
On their journey, Corey and Jimmy cross paths with a spirited girl named Haley Brooks, played by Jenny Lewis, who is making her way home to Reno. Discovering Jimmy's unexpected talent as a video game whiz, Haley, nicknamed him "the Wizard," tantalizes the duo with tales of "Video Armageddon," a prestigious video game tournament boasting a staggering $50,000 cash prize. Enthralled by the opportunity to prove that Jimmy deserves independence from institutional life, they enlist Haley's help to reach Los Angeles with the aim of competing for a share of the winnings.
As the trio journeys across the country, they capitalize on Jimmy's skills to hustle unsuspecting players out of their money in video game showdowns. Their adventures lead them to encounter Lucas Barton, a popular preteen with a Power Glove, is played by Jackey Vinson, who reveals his intention to enter the same tournament. Upon reaching Reno, Haley shares her motivation for wanting a piece of the prize money: to assist her father in purchasing a home. They receive crucial help from a trucker acquaintance named Spanky, and with the winnings from the craps tables, they train Jimmy at local arcades, specifically using Nintendo PlayChoice-10 machines to hone his gaming prowess.
However, the journey is fraught with challenges, as Putnam repeatedly tracks down the wandering trio, capturing and then losing Jimmy twice through a series of misadventures. The ultimate showdown occurs at Universal Studios Hollywood, where the tournament unfolds in the iconic Spartacus Square. After a rigorous preliminary round playing Ninja Gaiden, Jimmy manages to secure his place as a finalist. As the competition intensifies, Putnam's relentless pursuit of the kids disrupts the event, nearly causing Jimmy to miss out on the final round.
In a climactic battle, the Woods family, the Bateman family, and Putnam converge in the audience as Jimmy faces off against Lucas and a third finalist in a game of Super Mario Bros. 3, a title that had yet to be released in the United States at that time. In a nail-biting finish, Jimmy clinches victory just moments before the timer runs out, discovering a Warp Whistle that catapults him into triumph.
As they embark on their journey back home, the family pauses at the Cabazon Dinosaurs, an intriguing tourist attraction. Overcome with excitement, Jimmy leaps from the vehicle and dashes into one of the colossal dinosaurs. Inside, he pulls out a cherished photograph of Jennifer taken during a family vacation at the dinosaur's feet. This poignant moment strikes Corey as he realizes that Jimmy simply wanted to leave behind a piece of his sister's memory where she would find joy. After placing the lunchbox inside the dinosaur, Christine kindly urges Sam to drive the boys and Haley home. In a heartwarming farewell, Haley kisses both Jimmy and Corey, prompting a tender peck on the cheek for Haley from Jimmy, encapsulating the bond they've formed throughout their adventure.
