The creatures began attacking years before the start of the story proper (we get the history in a prologue). The humans can't fight the monsters by conventional military means because it causes too much collateral damage. They created the robots — called Jaegers — to engage them directly, before the creatures, called Kaiju, could make landfall. Over time the beasts have become bigger, nastier, more resourceful, as if they're evolving. And now they seem to be winning. Humankind is in retreat.

The fight scenes are often shot too close-in for my taste, and they go on too long, particularly during the final stretch — a problem that also afflicted"Iron Man 3," "Star Trek Into Darkness," "Man of Steel" and other recent summer films — and there are times when one of the combatants will use a weapon so devastating that you wonder why they didn't just haul it out at the start of the fight and make the punching, kicking and flipping unnecessary.

Nitpicks aside, though, the fights are astonishing. They split the difference between classical filmmaking and the blurrier, more chaotic modern style in a way that made me appreciate the virtues of both. Some of the whirling action has a geometric beauty that's faintly Cubist, and each fight contains surprises: a tactic you haven't seen yet, a power you didn't know about, a complication you didn't see coming.

But for all its mayhem, "Pacific Rim" is a film with more more emotion than its trailers could have led you to expect. The hero, Raleigh Becket (Charlie Hunnam) is an ace pilot who gave up robot-piloting for coastal wall-building when his partner and older brother Yancy (Diego Klattenhoff) died fighting a monster. The pilots don't just share physical responsibilities, they have unfettered access to one another's memories, and must struggle not just to control their thoughts during combat, but to avoid being thrown off when their co-pilot lets a distracting or traumatic image slip through.

Raleigh thinks the bond he had with his brother can never be replicated, that his loss was irreplaceable. He learns otherwise when he's paired with a young woman named Mako Mori (Rinko Kikuchi), who lost her parents in a Tokyo monster attack many years earlier. The story of their burgeoning partnership is not just that of pilot/copilot, but brother/sister, or friend/friend (but not boyfriend/girlfriend, refreshingly). It's about learning to trust another person enough to allow their consciousness to fuse with yours.