Clean-cut Hugh Carver, a promising freshman, arrives at Sanford College with lofty ideals. His focus on academics and sports is quickly derailed when he falls for popular flapper Cynthia Day and her modern, carefree attitude plus—as the title suggests—her bold red lips. As Hugh is drawn into a world of jazz, late-night parties, and "petting" sessions, his grades suffer. As he struggles to balance the temptations of the era’s rebellious youth culture with his personal integrity and athletic ambitions Hugh must decide if his romance with Cynthia is worth the potential ruin of his future.