One imagines Terry Gilliam at his laptop plotting his next screenplay. He’s unsure of the eventual outcome but certain in one regard: there will be dwarves, time travel, a scrumptious young female lead, and men dressed in a Middle Ages-meets-steam punk mix of tattered clothes and stringy hair. If you can count on Gilliam for anything, you can depend on the British director for the patented antiquated, murky, visually chaotic worlds he creates in his well budgeted but ramshackle films — The Brothers Grimm, 12 Monkeys, The Fisher King, and Tideland. In Gilliam’s fantastical creations it makes perfect sense for giant Monty Python heads to bubble up from the earth like geysers, for black rivers to turn into hideous serpents with human faces, or for the devil to make an appearance in human form. Gilliam’s film world may appeal most to phantasmagoria junkies — people who crave visual excitement, but have less concern with continuity, logic, or the traditional three-act storyline.

The film begins with the appearance of an enormous, multistoried gypsy wagon — like a double decker bus rendered in wood and held together with tree sap — careening through the streets of contemporary London. On board is the boozy patriarch Doctor Parnassus (Christopher Plummer), his 15-year-old daughter Valentina (Lily Cole, the Terry Gilliam ideal with an angel face and voluptuous body), a handsome young helpmate Anton (Andrew Garfield) with a hopeless crush on Valentina, and the requisite medieval midget Percy (Verne Troyer) who cuts everyone down to his size with a stream of wisecracks and verbal jabs. The quartet park outside of rowdy London pubs and big box shops in the dead of night to perform an outdated stage show centered upon a mirror, the Imaginarium, that provides a portal to the unconscious. When people pass through the portal they strike a kind of devil’s bargain: their fantasies and wishes seem to come true, but if they stay too long, their fondest dreams are punished with a taste of hellfire courtesy of a journeyman devil. The devil is played by the gravel-throated retro crooner Tom Waits wearing a pencil mustache and malevolently sucking on a stogie. In an ill-advised deal with the devil, centuries ago, Parnassus traded his first born child to Mr. Nick (Waits) in exchange for immortality. As Valentina’s 16th birthday arrives, it is time for the devil to claim his prize.

Gilliam’s films tend to be as baroque as their backstory: budget overruns, onset disasters, and in the case of Imaginarium, a movie star, Heath Ledger, who died tragically during the making. In a creative response to Ledger’s death, Gilliam happens upon a remedy. When Tony passes through Parnassus’s magic mirror into the fantastical parallel universe, he is played, in turn, by Johnny Depp, Jude Law, and Colin Farrell. Unfortunately, Ledger’s talent is dreadfully under-served in the mess of Imaginarium. Ledger plays a mystery man, Tony, rescued by the Imaginarium crew from an apparent suicide attempt hanging on the underside of a London bridge. He is embraced by the quartet, despite his amnesia, which has conveniently erased his possibly criminal past.

The Imaginarium of Doctor Parnassus mixes Gilliam’s usual visual excesses; a blend of his absurdist Monty Python impulses, Ingmar Bergman-style lyricism, and his usual fascination with society’s outsiders. But plot, such as it is, seems less critical in Gilliamville, than the director’s beloved atmosphere, which again takes center stage in The Imaginarium of Doctor Parnassus. Even expository dialogue seems irrelevant. In Imaginarium, characters, especially Ledger, mumble their lines in an echo of the jumbled, chaotic tableaux. The Imaginarium is a typical Gilliam muddle, full of crazed, often inspired imagery (a sequence where Tony scales an enormous ladder into heaven inside the Imaginarium is especially thrilling). But it is difficult to be awed by Gilliam’s imagination when it is so consistently unyoked to story and seems more about the director’s own creative satisfaction than bequeathing his audience some reward for their time.