Seventeen-year-old Richard Samuels (Zac Efron) spends his days dreaming of the bright lights of Broadway. He gets his big break when he happens upon Orson Welles (Christian McKay) and his fledgling Mercury Theatre company. Richard impresses Welles with an impromptu audition and lands a bit part in the Mercury's forthcoming run of Julius Caesar.

With Welles's womanizing taking priority over rehearsals, chaos and calamity mark the production from the start. Before long, opening night has arrived and Richard will discover the terrible secrets of show business.