“You mean, you stop telling the story and the whole universe ceases to exist?”

Few filmmakers have the cachet to rope in talent like Colin Farrell, Johnny Depp, and Jude Law. Fewer still could convince a trio of that caliber to take turns playing the same character in a fantasy film that centers on a thousand-year-old mentalist (Christopher Plummer). But that’s exactly what happens in Terry Gilliam’s The Imaginarium of Doctor Parnassus, which was left incomplete when star Heath Ledger passed away in 2008. Instead of starting anew or scrapping the project entirely, Gilliam and co-writer Charles McKeown elected to retool the eccentric narrative to incorporate a shape-shifting scoundrel who invades the lives of a close-knit carnival troupe (Plummer, Andrew Garfield, Verne Troyer, Lily Cole) as they ply their trade while roving about modern day London. The centerpiece of their nightly magic act is the titular Imaginarium—a mystical world entered through a mirror that conforms to the deepest desires of those who enter and allows the director to throw a million ideas on the screen, all brought to life by a mix of slapdash practical and visual effects. When Ledger’s mysterious drifter is found hanging by the neck and rescued by the entertainers, he repays them by adding an element of showmanship to their performance, a development that irritates Mr. Nick (Tom Waits), AKA the Devil himself, who has been engaged in a prolonged battle of wits with the ancient sage and has come to collect his debt for a wager made long ago.

Much better in its imaginative second half than in the early going (where it seems Gilliam used all the footage of Ledger he had, which isn’t all great), The Imaginarium of Doctor Parnassus provides a smorgasbord of pleasant self-references—various elements recall Monty Python and the Holy Grail (1975), Time Bandits (1981), The Adventures of Baron Munchausen (1988), and The Fisher King (1991), while the eponymous thaumaturge is clearly a surrogate for the filmmaker himself, representing his lifelong mismatch with the Hollywood system—but it won’t amount to much more than an offbeat curio for those who could take or leave the director’s unique style and thematic preoccupations.

But there’s an undeniable charm to its shagginess, perhaps bound up in Ledger’s death, the film’s elegiac touches, and the fact that his three buddies signed on with the proviso that their wages be donated to his daughter; perhaps derived from the film’s nebulous narrative logic which camouflages a number of gaping holes with ramshackle spectacle; perhaps because it features Andrew Garfield in a fat lady suit and then later with his face grafted onto the body of a child. It certainly doesn’t cohere all that well, but it’s a lot of fun to be tugged along on this magical journey as it frenetically meditates on the importance of storytelling.