No one could accuse director Terry Gilliam of a deficit of imagination.

No one could accuse director Terry Gilliam of a deficit of imagination.

From his highs - the bureaucratic futurescape of Brazil and Hunter S. Thompson's hazy drug diary Fear and Loathing in Las Vegas - to recent lows like the big-budget Brothers Grim and the creepy mess of Tideland, Gilliam's wild style is ever present.

His latest film will grab headlines as Heath Ledger's last, but it's just as noteworthy as one of Gilliam's best, despite the improvisation required by Ledger's death.

The Imaginarium of Doctor Parnassus follows a theater troupe traveling the streets of modern-day London with a horse-drawn stage and a flair for circus sideshow dramatics.

The aged Parnassus (Christopher Plummer) is accompanied by his young daughter Valentina (Lily Cole), assistant Anton (Andrew Garfield) and right-hand dwarf (Verne Troyer). Their rickety stage makes the show seem like a scam, but its centerpiece is a mirror that actually transports audience members into a world of imagination come true.

As Valentina's 16th birthday approaches, Parnassus is visited by his devilish nemesis, Mr. Nick (Tom Waits), looking to collect on a bet with Valentina as the prize. Meanwhile, an unusual encounter brings a new member to the troupe, the memory-lapsed Tony (Heath Ledger).

Ledger's death during filming left Gilliam contemplating scrapping the entire film, but a rewritten script provided a way for three of Ledger's colleagues - Johnny Depp, Jude Law and Colin Farrell - to complete the role. It takes a bit of Imaginarium trickery, but Gilliam manages to minimize the distraction of four actors playing one part.

Ledger's performance won't eclipse his Joker, but some of the same wicked charms are on display, and it's a fitting swan song. Plummer is superb, particularly when verbally sparring with Waits' gravel-voiced devil (that casting was inspired).

A noted critique of Gilliam, particularly in his more off-the-rails projects, is that he's too self-indulgent. The charge is true here, and some are sure to get lost (and bored) in this labyrinth of a plot, even amid the dazzle of the effects-driven Imaginarium sequences.

But Gilliam's boundless imagination and knack for dark fairy tales makes Parnassus a true joy for those willing to go through his mirror.