When hedonistic but charming con man Elmer Gantry (Burt Lancaster) meets the beautiful Sister Sharon Falconer (Jean Simmons), a roadside revivalist, he feigns piousness to join her act as a passionate preacher. The two make a successful onstage pair, and their chemistry extends to romance. Both the show and their relationship are threatened, however, when one of Gantry's ex-lovers (Shirley Jones) decides that she has a score to settle with the charismatic performer.