In the year 1951, we find ourselves in Anarene, a small oil town in Texas, where two high school seniors and best friends, Sonny Crawford and Duane Jackson, are navigating the complexities of youth. While Duane is romantically involved with the stunning and affluent Jacy Farrow, Sonny grapples with his feelings after ending his relationship with Charlene Duggs. Unbeknownst to Duane, Sonny harbors a secret love for Jacy that complicates their friendship.
The plot thickens during a festive Christmas dance where Jacy is invited by Lester Marlow to join a hedonistic skinny-dipping party at the luxurious home of wealthy Bobby Sheen. Meanwhile, Sonny shares a kiss with Ruth Popper, the melancholic wife of his high school coach, adding to the emotional entanglements. At the party, Jacy faces Bobby's advances but is met with disappointment when he reveals he won't be intimate with virgins.
In a misguided attempt to assist their friend Billy, who has mental disabilities, Duane and Sonny take him to a prostitute. Back home, local businessman Sam "The Lion" becomes infuriated at how they treat Billy and bans them from his establishments—the only spots for entertainment in Anarene. However, as Sam notices Sonny's genuine care for Billy, who is often found tidying the dusty streets with a broom, he allows Sonny back into his café.
As New Year's approaches, Duane and Sonny embark on a road trip to Mexico, receiving a wistful send-off from Sam, who offers them money for their adventure. Upon their return, they are met with the shocking news of Sam's sudden death from a stroke, leaving the pool hall to Sonny in his will.
In a turn of events, Jacy invites Duane to a motel room for intimacy, driven by her desires for Bobby's acceptance. After a humiliating experience where Duane struggles, Jacy exits the relationship and seeks to be with Bobby, only to find him married. In her frustration, she ends up with Abilene, a foreman known for his rough demeanor, but is met with emotional coldness. Later, a confrontation with her mother Lois reveals their shared grievances against the treatment they receive from men.
Fueled by heartbreak, Duane enlists in the Army, facing deployment for the Korean War. Jacy then pursues Sonny, prompting him to end things with Ruth and dream about a life with her. When Duane returns on leave with a new car, tensions escalate, resulting in a fight that leaves Sonny injured and hospitalized.
In a moment of impulsive passion, Jacy and Sonny elope, but their joy is short-lived when they are intercepted by Jacy's father Gene Farrow, leading to their marriage being annulled shortly thereafter. Time passes, and on the last night of Duane's leave, the two friends reconcile. They share a bittersweet trip to the nearly forgotten local movie theater, where they watch the "Red River," the last film to be screened before its closure.
Their world darkens the following day when Sonny witnesses the tragic death of Billy, inadvertently blamed by local men. Overwhelmed by grief and anger, Sonny scolds the townspeople, tenderly carrying Billy's body away to honor his memory. This heartache propels Sonny towards the city limits, but he hesitates and returns to Ruth's home, seeking solace. A poignant encounter ensues as Ruth expresses her own pain and, despite their shared troubles, they connect in a moment of vulnerability that hints at possibilities for healing.
