Neil Gaiman and Dave Mckean first collaborated in the late eighties on comics that changed the genre. In Mirrormask, they have attempted to perform a similar transformation on the needier genre of family fantasy films.

Mirrormask opens in a carnival, where the indeterminably teen-aged Helena (Stephanie Leonidas) juggles alongside her mother and father (Gina McKee and Rob Brydon). She just wants to sit in her room and draw more of the baroque pen and ink sketches that wallpaper it, so she fights with her mother before going out into the ring. Her mother passes out during the performance, and Helena and her father find themselves staying with an aunt in a bleak project of the solid-block-of-concrete variety while Helena's mother is treated for cancer. One night, Helena falls asleep and finds herself in a CG dreamworld that looks amazingly like her art.

Helena's world is a beautiful place, as those familiar with Dave McKean's work would expect. It is oddly two-dimensional, because many objects lie on pieces of paper that the characters walk around and through. Even body parts are sometimes made of paper. But it can also be stunningly three-dimensional, as when Helena encounters giants orbiting above a forest of observation platforms. Because there is no real attempt to make the world realistic, the movie feels like a picture-book—in fact it reminded me a great deal of Gaiman and Mckean's wonderful earlier collaboration “The Day I Swapped My Dad for Two Goldfish.” This is no flaw—the story is still told clearly, and the stylized approach to cinematography feels fresh and interesting.

But, of course, the movie needs a plot as well, and this is where things come apart. Helena's dream is a simple quest tale: The White Queen is unconscious and her city is dying around her, destroyed by a darkness emanating from the city of the Dark Queen. The Dark Queen is desperately seeking her daughter who ran away from home. Helena, accompanied by a performer named Valentine (Jason Barry), must find the Mirrormask and the Dark Queen's daughter in order to save the dreamworld and return to her own. This is the stuff of fable, and like many fables, this one is mostly about the real world. For example, the inhabitants of the White City have no faces, just masks, and Gina Mckee plays both queens as well as Helena's mother. The other metaphors are nearly as transparent.

And this is the central problem. The fantasy world, for all its beauty, is incredibly dull. There is no character development, except in the broadest strokes; no insight, except the most banal; there is no subtlety. Helena gets to act out her adolescent rage against her mother in the safer, more transparent language of her dreams. The real pain of Helena's anger gets displaced onto the Dark Queen's daughter, who we occasionally glimpse occupying Helena's waking life. It's almost as if the filmmakers don't believe that real characters can inhabit a fantasy, that they see the only role of fantasy as allegory. Given what I know of Neil Gaiman, this can't be true, so I'm left with the conclusion that this time around they just got lazy. That's a shame, since Mirrormask could have been an excellent film. It will have to settle for being filled with pretty pictures.

Alex Saltman is a string theorist at Stanford and has written for Wired and New Scientist.