When Smurfs go bad.

The summer movie season gets off to an exhilarating start with X2: X-Men United, the first sequel to 2000's hit about good and evil mutants and the humans who fear them. And with all the exposition taken care of in the first film, this one is free to jump right into a story that's heavy on the action, if a bit light on characterization.

For the uninitiated, the X-Men movies are based on the Marvel comic book series of the same name. They take place in a world where some people are born with genetic mutations that give them extraordinary powers, and the rest of us really resent them for it. The good guys, led by powerful telepath Professor Xavier (Patrick Stewart), run a school for "gifted" children by day, save the world by night. Their archenemies are Magneto (Ian McKellen), who has power over all things metal, and his shape-shifting henchwoman Mystique, played by blue-skinned boy-bait Rebecca Romijn-Stamos. These two groups of mutant enemies have to team up to fight General Stryker, a man who's fanatically devoted to getting them out of the gene pool and isn't above manufacturing a little anti-mutant hysteria to do it.

"I'm sorry, you must be this tall to ride this ride."

Of course the story mostly provides a framework for a series of spectacular action sequences. I particularly liked the opening scene where a teleporting mutant attacks the President in the Oval Office, blinking in and out, dispatching Secret Service agents before disappearing again in a plume of smoke. Throughout the movie, the special effects are dazzling, the action clever and creative and together they're a lot of fun.

There's also a message woven into all the eye candy about the importance of civil liberties and tolerance for others. The "we're here, we're mutated, get used to it" theme is far from subtle, but it doesn't get overplayed either, and it gives the movie some much-needed heart.

Straight-to-video sequel Edwina Scissorhands didn't really have the magic of the original.

The individual stories of the X-Men don't play out quite so successfully. In that regard, I liked the first movie a little better; I felt like we got to know each of the characters and some of them actually grew in meaningful ways. This time around, their personal story arcs seem poorly thought out. The love triangle between Logan, Jean Gray and Cyclops falls flat. There's a sub-plot about Jean growing more confident in her powers (telepathy and telekinesis, to be exact) that is told more than it's shown. The amnesiac Logan's internal conflict, between learning the secrets of his tortured past and embracing his future as a hero, is the intriguing exception, due in large part to Hugh Jackman's intense performance.

The X-Men universe, with its seemingly endless supply of angst-ridden outsiders, may be able to avoid the repetitiveness that plagues many super-hero franchises. If they manage to weave a little more character development into the mayhem next time around, well, that would be a real evolutionary leap forward.

Gorilla Pants rating: 3 out of 4 bananas