(CNN) Kids saving the world is among literature's more durable ideas, and there's been a whole lot of that since "A Wrinkle in Time" first published in 1962. Yet director Ava DuVernay's splashy adaptation seldom conjures the magic to which this big-screen exercise aspires -- not a complete waste of time, certainly, but too mundane to provide a consistently good one.

There's a simplicity to Madeleine L'Engle's book, which was previously turned into a TV movie. Expectations are raised, however, by the prospect of a Disney-backed blockbuster broadly aimed at a family audience, which might explain why this "Wrinkle" keeps swelling to a crescendo (augmented by music from "Game of Thrones" composer Ramin Djawadi), in a way that risks overwhelming its slim framework.

DuVernay made a shrewd move by enlisting Oprah Winfrey as one of her co-stars, which blesses the project with the billionaire's coveted seal of approval as well as her marketing clout. The tradeoff, though, is that her presence accentuates the underlying message of self-empowerment and learning to love oneself, in a way that makes the movie feel a bit more like an inordinately lavish after-school special than it otherwise might.

The story centers on Meg (Storm Reid), an unhappy outcast at school, as she nears the fourth anniversary of the disappearance of her father (Chris Pine), a scientist who had been exploring grand universal forces. The pain of that loss has made Meg a handful for her mother (Gugu Mbatha-Raw), and highly protective of her younger brother Charles Wallace (an adorable Deric McCabe), a pint-sized genius with a slightly elfin streak.

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Charles Wallace pretty quickly introduces Meg to a trio of magical benefactors -- played by Winfrey, a sprightly Reese Witherspoon and Mindy Kaling -- who have come to recruit warriors, looking to repel The It, a shadowy evil that as described sounds like a close cousin of "Star Wars'" Dark Side of the Force. If left unchecked, Meg is warned, "darkness will fall across the universe."

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