What an absurd creation -- the Teenage Mutant Ninja Turtles. Way back in the 1980s, they were an experiment borne out of boredom with the mainstream comic world, created by comic greats Kevin Eastman and Peter Laird as a rebellious backlash to the silliness that dominated their world at that time.

But today, the four masked amphibians have become some of the most bankable icons of the mainstream -- the center of a merchandising maelstrom that has come to be one of the most profitable in comic history.

Back in the early '90s, the turtles made their first transition from the small screen cartoons to the main stage, commanding not one, not two, but three feature films that drew in millions of dollars and thousands of fans. Something about these heroes of the half shell, all named after famous Italian artists, all fans of pizza and all students of a mutant rat who somehow became an expert in all things ninjitsu, became a popular draw with America's kids, moving from the fringe to the middle of a world populated by the heroic Batman, the infallible Superman, and the just-your-everyday-superhero Spider-Man.

But what so few "Turtles" fans realized back then is just how serious these green gurus could be -- how dark this silly world of turtles was originally intended to be.

For that's how "Teenage Mutant Ninja Turtles" truly started -- not just as a silly, preposterous Saturday morning cartoon, but as a band of darker, meaner heroes of the night who lashed out against their villains in black-and-white comic books that played down the laughs and played up the action.

Enter "TMNT," the fourth "Teenage Mutant Ninja Turtles" film to reach the big screen, and a throwback to this earlier, more serious vision of the four sewer samurai.

It's a world carefully crafted in all its CGI sophistication by director Kevin Munroe, a longtime "Turtles" fan who begins this tale in the middle of the jungle, where explorers have long heard the legend of a mystical force living in the trees. Suddenly we see the eyes of Leonardo, one of our four men in green blending in with the foliage, who quickly jumps down on his invaders, and uses his ninja skills to disarm and defeat.

He is the leader of this turtle foursome, the eldest who has been sent away from home to refine his skills for years while his younger brethren have been left behind told to fend for themselves in New York City. In the months and years since Leonardo left, his three brothers have turned to their own interests. Michelangelo, the group's comic relief, has turned to entertaining kids at birthday parties, while Donatello, the gang's technical expert, has become an online tech assistant and Rafael, the ill-tempered younger anti-hero, has been setting out secretly as one of the city's most popular super heroes.

The actual plot of "TMNT" is rather tedious, and not all that important. A rich man (voiced by Patrick Stewart) wants to assemble a number of ancient artifacts that, when fused together, promise to reopen a portal to the past and allow him to break a curse.

But what happens instead, as this man dispatches a surreal army of ninjas-for-hire and giant stone soldiers straight out of a science fiction story, is a surprisingly intense fight along the New York City skyline.

In scenes of fast-paced, hand-to-hand action, Munroe shows the Turtles jumping between high-rise buildings and descending on this ninja army, a series of fights and brawls playing out with a sense of realism never before seen in a "Turtles" movie before. And in one notable scene, as the rain falls down around them, the battle even turns inward, as two of the brothers allow their tempers to flare and their anger to turn on each other.

What we realize halfway through "TMNT" is that while it's fun to be a turtle, and fun to be a superhero, there are also challenges that go along with that power.

If the first three big-screen "Turtles" films were comedies with action, then "TMNT" is an action film with doses of comedy, repositioning this turtle squad as not silly heroes of the '90s but more serious, thoughtful, even complicated heroes of 2007. The Turtles are back -- and as they say, new and improved.

by: Steven Snyder steven@zertinet.com, Published 2007-03-26