Dr. Parnassus (Christopher Plummer), the leader of a traveling show, has a dark secret. Thousands of years ago he traded the soul of his daughter, Valentina, to the devil. Now the devil has come to collect his prize. To save her, Parnassus must make a final wager: Whoever collects five souls first will win Valentina. Tony (Heath Ledger), a man saved from hanging by Parnassus' troupe, agrees to help collect them, with his eye on marrying Valentina.