In early 1900s Mississippi, an eleven-year-old boy named Lucius McCaslin is growing up under the strict yet loving guidance of his grandfather. When the elder McCaslin buys a bright yellow Winton Flyer automobile, it becomes the town's centerpiece of attention. Boon Hogganbeck, a family friend and handyman, views the car as an opportunity for adventure. One weekend when the elder McCaslin is away, Boon convinces Lucius to "borrow" the car for an unapproved trip to Memphis. Accompanying them is a stowaway, the skeptical yet resourceful stable hand named Ned.

Their journey is filled with comedic mishaps and moral lessons as they navigate through unfamiliar territories, racing against time and circumstances to return home before they are discovered. Lucius is exposed to new experiences that challenge his understanding of right and wrong. The bond among the trio is tested and deepened as they encounter both kind-hearted strangers and deceitful opportunists. Each character is irrevocably changed by the journey, bringing fundamental revelations that reshape their perspectives on life and family. What follows is a tale rich in adventure, tempered by the unfolding complexities of human nature.