There are no Prince Charmings in Pixar’s new animated adventure “Brave,” no knights in shining armor. For the most part, the men in this arresting and affecting movie – set in an enchanted Scottish kingdom an undetermined number of centuries ago – are content to booze and brawl and leave the business of running things to the women.

The heroine is a tomboyish teenage princess named Merida (voice by Kelly Macdonald), who has porcelain-white skin, saucer-like blue eyes and a flaming and unruly nest of red curls. At the start of the film, she is fighting against her parent’s dictate that she must be betrothed to one of the eldest sons of the kingdom’s most respected families.

That sounds like a familiar fairy-tale theme, but “Brave” dares to take Merida’s side in the debate: I can’t think of another children’s movie so resolutely and proudly unconcerned with finding a square-jawed hunk for its heroine to settle down.

Yet what propels “Brave” is a genuine belief in the transcendent power of an independent mindset – it understands and illustrates that you have to define the terms of your own self before you can even think about pairing off. Merida’s defiance of her parents isn’t “plucky” and “cute,” in the manner of most Disney princesses; when she grabs her bow and arrow and takes to the archery field to win the right to choose herself as her spouse, you get the sense that she’s desperately fighting for her life.

Recent movies like “Tangled” or “The Princess and the Frog” pay mere lip service to the notion of girl power, but this one redefines it for an era where gender roles are so infinitely complicated. If the boys don’t like it, “Brave” says, well, tough.

The opening section of the picture is the most conventionally earthbound. As three hapless suitors compete to win her hand, Merida struggles to convince her father (Billy Connolly) and mother (Emma Thompson) that she should be allowed to pursue love on her own terms.

The movie really takes off, though, when Merida heads into the forest, following a series of glowing blue will-o’-the-wisps, all the way to the cottage of a mysterious woodcutter (Julie Walters), who may not be what she seems. The less said about the strange spells and beastly transformations that follow, the better.

It spoils nothing, however, to marvel over the way “Brave” never oversells its supernatural elements, and instead creates a completely plausible world where the ordinary, the surreal and the mythological all happily co-exist and bleed into one another. What makes the fantasy work, of course, is that it’s also wedded to an abiding sense of humanity – the final act of “Brave” turns into an epic story of mother-daughter reconciliation, like “Terms of Endearment” with snarling bears and a chase through the forest instead of terminal illness.

If there’s a real gripe to be made about the picture, it’s the same gripe I had with “The Avengers” and “Prometheus” and “Men in Black III” – at least in the theater where I saw the film projected, the 3-D rendered the images much too dark. For some of the scenes in the forest, this may very well be the point. But when an entire movie – one meant for children, no less – looks like it’s taking place in really overcast weather, clearly the technology needs some refining.

My best advice, then, is to see “Brave” in traditional 2-D, where the indomitable spirit of Merida – an animated heroine who deserves to achieve the one-name celebrity status of Ariel or Belle or Cinderella – should completely light up the screen.