Following the travelling show of the mysterious Dr. Parnassus (Christopher Plummer), a man who once won a bet with the Devil himself and possesses the unique ability to guide the imagination of others. Many centuries ago, Dr. Parnassus won immortality in a bet that found the malevolent Mr. Nick (Tom Waits) coming up short.
While few would be foolish enough to try their luck against the powers of darkness a second time, Dr. Parnassus did precisely that, this time trading his mortality for youth on the understanding that his first-born would become the property of Mr. Nick when the child reaches his or her 16th birthday.
Flash-forward to the present day, and Dr. Parnassus' daughter, Valentina (Lily Cole), is about to celebrate her sweet sixteen. Dr. Parnassus is desperate to save his little girl from her fiery fate, and when Mr. Nick arrives to collect, the good doctor presents the Prince of Darkness with a wager too enticing to refuse.