In an impromptu journey, Charlie Babbitt, a young car salesman, discovers that his deceased father, whom he barely knew, has left behind an unexpected fortune. However, the inheritance is not what he expected: most of it is destined for his older brother, Raymond, an autistic man with exceptional abilities in numbers. Desperate to access his share of the inheritance, Charlie kidnaps Raymond from the home where he lives. As the two men embark on a road trip to Las Vegas, Charlie seeks to exploit his brother's skills to win at the casinos.
The relationship between the two brothers begins to evolve. Charlie, who initially sees Raymond only as a means to get money, starts to understand and appreciate the uniqueness and beauty of the world through his brother's eyes. As they share bittersweet moments, time jumps, and comedic situations, the family dynamics and Charlie's internal struggle to accept Raymond become more evident.
While numbers and gambling odds punctuate their lives, unexpected emotional growth takes place. The film takes the viewer on a journey that not only explores the brotherly relationship but also challenges perceptions of autism and intelligence. In the end, what initially appeared to be merely a pursuit of money transforms into a life lesson about connection, love, and acceptance.