In the depths of the Great Depression, Robert Syverton, a wandering soul burdened by his past, finds himself caught up in a bizarre dance marathon at Santa Monica Pier. Upon entering the dismal ballroom, he discovers couples in a frenzied bid for a $1,500 prize, hoping to attract the fleeting glances of Hollywood's elite. Robert is drawn into a partnership with the troubled Gloria Beatty, portrayed by Jane Fonda, after her previous dance partner is struck down by bronchitis. This diverse group of participants also includes the grizzled ex-sailor Harry Kline, the aspiring actress Alice, who hails from London, and her actor-in-training friend Joel, alongside James and Ruby, a destitute farming couple eagerly awaiting their first child.
As the marathon progresses, the fragile alliances start to unravel. Rocky, the shrewd promoter, played by Gig Young, astutely exploits the weaknesses of the contestants for the audience’s amusement. The event becomes a breeding ground for quack medicine and emotional turmoil, where participants endure both physical and psychological abuse under the guise of treatment. Tension mounts when Rocky pilfers one of Alice's dresses to spark manufactured drama, igniting Gloria's jealousy over Robert's growing attention towards Alice. The dynamics shift as Gloria seeks solace in new alliances, particularly with Joel and later with Harry, whose sudden death during the marathon starkly illustrates the life-threatening pressures of the competition. Despite the chaotic scenes that follow Harry's untimely demise, including the medics hastily removing his body, Rocky orchestrates a ruse to shield the audience from the grim reality.
As the competition intensifies, Alice's mental state deteriorates, prompting a rare moment of compassion from Rocky, leading her to withdraw for essential medical attention. With their former partners sidelined, Robert and Gloria are once again paired, navigating the increasingly treacherous waters of the marathon that heads toward its dramatic finale. Amidst their struggles, Rocky devises a plan—pairing Robert and Gloria in a marriage would attract sympathy and financial support from benefactors like Mrs. Laydon. However, Gloria rebuffs this idea, and Rocky reveals a harsh truth: expenses will slice through their prize winnings, potentially leaving them empty-handed.
Overwhelmed by despair, Robert and Gloria decide to forfeit the contest and leave the dance hall behind. As they step onto the pier, a broken-hearted Gloria confides in Robert about her relentless emptiness and her weariness of life itself. In a tragic moment of vulnerability, she brandishes a gun from her purse, contemplating her own fate but lacking the resolve to pull the trigger. Instead, in her moment of anguish, she implores Robert to grant her peace. In a devastating turn, he complies, resulting in the arrival of authorities to take Robert into custody and carry away Gloria's lifeless body. When interrogated about his actions, Robert's chilling response echoes, “> They shoot horses, don't they?” The marathon trudges on, with fewer participants remaining as the hours tick away—1,491 and counting.
