When a computer-animated reinvention of the "Teenage Mutant Ninja Turtles" franchise was first announced, it sounded more like a weird joke than a valued promise. After all, hadn't these crime-fighting reptile siblings grown into relics of the late-'80s/early-'90s? Did anyone still remember them in 2007? Did anyone, including now-grown men who, like me, were the young target audience when the live-action "Teenage Mutant Ninja Turtles" movie came out in 1990, still care? My guess to the answers of these questions would be yes, no and no, but that hasn't stopped Warner Bros. and writer-director Kevin Munroe from embarking on what has to be one of the worst film ideas of the year. "TMNT," as the illiterate-friendly updated title now stands, is outdated, irrelevant, strictly generic junk that could very well deaden the brain cells of children everywhere if this thing defies the odds and becomes a box-office hit.

Set after the events of 1993's "Teenage Mutant Ninja Turtles III," archnemesis Shredder has finally been defeated and half-shelled brothers Leonardo (voiced by James Arnold Taylor), Donatello (Mitchell Whitfield), Michelangelo (Mikey Kelley) and Raphael (Nolan North) have drifted apart. Donatello works as a telephone tech support man. Michelangelo is a costumed birthday party entertainer. Raphael sleeps all day and secretly prowls the NYC streets at night, searching for evildoers. When human friend April (Sarah Michelle Gellar) runs into Leonardo in the jungles of Central America, her talk of a once-tight family unit that needs saving convinces him to return to the Manhattan sewers. The quartet have a lot of catching up to do and a lot of issues to work out, but first they must stop thirteen ancient monsters from overtaking the world and send them back to their own times.

Charmless and repellent, "TMNT" is a chore to sit through and even more difficult to care about. The writing and direction by Kevin Munroe propose to be darker and grittier than in previous installments in the saga, but with a plot that is pure rubbish and forgettable characters who are haphazardly developed, the film takes itself far too seriously. When a "cowabunga, dude" reference or a cheesy one-liner squeaks out, it all the more sits out like a sore thumb and emphasizes how groan-inducingly bad it is. Were it not for their different colored bandanas that set them apart from one another, these four mutant turtles scarcely would seem like their old selves. No longer teens despite what the title says, less jokesters than morose whiners, and with a blink-and-you'll-miss-it cameo from their signature favorite food (pizza), Leonardo, Donatello, Michelangelo and Raphael have been circumcised into crushing dullards.

Opening with an unfortunate narration by Laurence Fishburne (2006's "Bobby") that only serves to lose grasp on the viewer's attention before the first minute is up, "TMNT" goes downhill from there. The premise is a meaningless trifle. The action—what there is of it—is so commonplace that it less resembles the razzle-dazzle of "The Incredibles" than one of those trashy "Pokemon" or "Yu-Gi-Oh!" movies. The computer animation ranges from good to embarrassing, with the early flashback to a "300"-style battle three thousand years ago not even up to video game standards. The exteriors of Manhattan are comparatively easier on the eyes, but it doesn't explore far beyond what was already shown in the theatrical trailers. In a film bereft of quality—if there is a point to be had or a lesson to be learned by the end, it went over my head—virtually the only moment that engaged my interest was a third-act fight in a city park. The outcome of the scuffle made no difference to me, but the trees in the background, furiously rustling in the darkness, looked awfully neat and atmospheric.

Whomever's bright idea it was to carry the Teenage Mutant Ninja Turtles into the twenty-first century—and as a theatrically-released animated effort, no less—should be handed no less than a year's worth of demerits. "TMNT" is hopelessly out of touch with the sort of quality it takes to play with the big boys of Pixar and (on a good day) Disney. The sibling bond and rivalry of the turtles is undistinguished by few scenes where a relationship is built between them, and a love story subplot between April and boyfriend Casey (Chris Evans) is equally dreary and uninteresting. With nothing to think about and no detectable imagination in effect, there is a deficiency of emotion and charisma in every aspect of "TMNT" that becomes downright depressing. Indeed, the only joy derived from watching it is the arrival of the end credits. White scrolling text on a black background has scarcely been so attractive.