PACIFIC RIM (PG-13) Deep beneath the waves of the Pacific Ocean, an inter-dimensional fissure has erupted, and it's spewing mammoth gigantic beasts from its darkness. The monsters, called kaiju, are laying waste to us puny humans and ravaging the earth. Humankind, however, is not taking this in stride. Faced with extinction, ingenious men and women have figured out a way to stave off total annihilation: construct giant robots commandeered by tag-team pilot warriors who will engage the kaiju with brute force. Colossal monsters and robots face off, and we all get to watch the damage with kid-frenzy delight.

Summer movies over the last decade—at least of the big, brawny Hollywood blockbuster sort—have tended to be mired in angst or warped from the strain of stupidity running riot through them. Mexican director Guillermo del Toro (Pan's Labyrinth, Hellboy II: The Golden Army) is arguably the finest fantasy filmmaker working today, a practitioner of dazzling imagery and aggressively creative action set pieces that cater unapologetically to geeks raised on comic books, anime, horror and science fiction. What makes del Toro stand apart from other directors of his kind, however, is his ability to root his fantastical stories firmly in character and a sometimes startling, thoughtful humanity. Del Toro's career, which has delivered the garish comic book delights of the Hellboy movies to the more complex hauntings of the brilliant The Devil's Backbone, offers up the visceral visual goods we crave in our genre movies, but he also knows how to pull back and allow poetry to subtly seep in. He's the real deal.

Pacific Rim is a thunderous experience and del Toro's most energetic spectacle yet. One of the most interesting aspects of his career is how he easily oscillates between brawny commercial features like Mimic and Blade II and more artistically substantial productions like The Devil's Backbone and Pan's Labyrinth, the latter two infused with the influence of Cocteau and Bava yet still entirely fresh. Pacific Rim wears its Japanese monster movie influence openly, though it is not del Toro at his best. The plentiful action sequences are visually coherent for the most part and far from the slick emptiness of the Transformers flicks, but ultimately it is simply big robots beating the hell out of towering monsters. But the movie is also exuberantly playful and inventive in its world-building. As summer blockbusters go, it's the most fun you'll have in a multiplex all season.