Dr. Parnassus (Christopher Plummer) has the extraordinary gift of inspiring the imaginations of others. Helped by his travelling theatre troupe, he offers audience members the chance to transcend reality by passing through a magical mirror into a fantastic universe. However, long ago, Parnassus made a deal with the devil and the time has come to pay his debt - give up his precious daughter, Valentina. Oblivious to her rapidly approaching fate, Valentina falls for Tony (Heath Ledger). In order to save his daughter and redeem himself, Parnassus sends Tony and the entire theatre troupe on a ride of twists and turns, in and out of London and the Imaginarium’s spectacular landscape.