"The Invasion" has had a notoriously rocky journey to theaters. Originally filmed two years ago, the film's scheduled release in August 2006 was abruptly pushed back a full twelve months when test screenings went unfavorably. Reshoots took place under the uncredited helm of the Wachowski Brothers (replacing director Oliver Hirschbiegel, who was by this time unavailable) and action scenes were added to buff things up. During one car stunt that happened to be recorded by an onlooker, Nicole Kidman was involved in an accident that sent her to the hospital for medical treatment. Now that "The Invasion" has finally seen the light of day, the question is whether or not it was worth all the trouble. The answer, as it so often seems to be with troubled productions, is no.

The fourth cinematic adaptation of the novel, "Invasion of the Body Snatchers," by Jack Finney, "The Invasion" is easily the biggest-budgeted of the lot and also the weakest. Its predecessors—the classy 1956 original, the exceptionally scary 1978 remake (still the best), and the lesser but still effective 1994 entry shortened to "Body Snatchers"—remained truthful to the themes and ideas of the source material, each one chilling in their portrayal of a beautifully flawed human society taken over by unemotional alien clones. "The Invasion" has a similar premise, to be sure, but it doesn't play fair with its audience and has cooked up a preposterously tacked-on and ill-advised ending that ruins the integrity of what has come before.

For the first time, the catalyst for the horrific takeover of the populace does not arrive in the form of space pods, but through a viral infection that is unleashed when a Space Shuttle breaks apart and plummets back down to Earth. Divorced D.C.-based psychologist Carol Bennell (Nicole Kidman) gets her first taste of the calamity to come when one of her patients, Wendy Lenk (Veronica Cartwright), claims that her husband is no longer her husband. Emotionally cold, distant, and prone to violence he feels no remorse over—he snaps the family dog's neck and throws the corpse into the garbage—Carol promptly tosses an anti-psychotic prescription Wendy's way upon hearing her story. It isn't long, however, before Carol suspects this isn't an isolated incident. As the city, and seemingly the rest of the world, experiences a mounting change in its citizens, Carol and best friend Ben Driscoll (Daniel Craig) set out to elude the virus and save her young son, Oliver (Jackson Bond), from the clutches of newly alien ex-husband Tucker (Jeremy Northam). What hope do any of them have, though, when said infection has the ability to take over bodies while they sleep?

"The Invasion" was directed by Oliver Herschbiegel (2005's Oscar-nominated "Downfall") and written by Dave Kajganich, whose screenplay was reportedly a hot Hollywood commodity that drew no less than the likes of A-list talent Nicole Kidman and a pre-007 Daniel Craig to the cast. Without knowing all of the particulars, one suspects that the film was deemed too cerebral and ruminative upon its first edit, and subsequent additions to the script during the reshoot phase dumbed its plot down and sped its pacing up to appease a wider mainstream audience. If this is truly the case, Warner Bros. made the wrong decision, throwing millions more dollars into a motion picture that would have been better off being left alone.

Just as clearly as a person in "The Invasion" can sense that those around him or her are no longer their human selves, the viewer can detect during the climax precisely where the intended finished product ends and the year-later filming takes over. The third-act, including an extended car chase, dozens of stuntman extras, fiery pyrotechnics, and several ramshackle story developments, is egregiously out of place from what has come before. As for the final couple scenes, they are such a cheap, cop-out ploy for a happy ending that they destroy the whole enterprise. It's one thing to alter a few details and update an older novel for modern times; it's quite another to gut out the thematic richness and overall intentions of a novel in the name of a rosy finish.

It is regrettable that there were too many cooks in the kitchen, so to speak, because "The Invasion" has a lot going for it. The opening hour and change is an elegantly shot and rendered sci-fi thriller, and director Herschbiegel does a fine job of depicting the paranoia Carol experiences as she helplessly witnesses the decay of human society. Top-notch location shooting in Baltimore and Washington, D.C. (including a rare on-film appearance of the city's Metro system) grounds the story's otherworldly elements in a basis of reality, and several scenes are appropriately skin-crawling. As Carol, Nicole Kidman (2005's "The Interpreter") is her usual reliable self, fully committing to her role as a woman desperate to reunite with her son even as hope for a tomorrow dwindles. As Ben, Daniel Craig (2006's "Casino Royale") is good in an underwritten part, his strongest moments being the lighter ones early on when his loving friendship with Carol is built up. It is also enjoyable to see Veronica Cartwright (2001's "Scary Movie 2"), who previously starred in the '78 version of "Invasion of the Body Snatchers," back in action as the distraught Wendy.

There is a thought-provoking scene in "The Invasion" where background news on the television reports on the war in Iraq ending and countries signing peace treaties with one another, suggesting that the world is at last becoming a place of widespread harmony. The irony of this is not lost on the viewer, who recognizes that in order to achieve such a thing the population would have to sell their souls and become emotionless drones. Had "The Invasion" simply brought up this hot-button notion and then left it at that, the film would have held an unexpected depth and power. Unfortunately, the movie feels the need to reiterate it and then blatantly spell it out a half-dozen times afterwards, drilling this idea so furiously into the viewer's head that it loses all sense of nuance and every ounce of its impact. That is the core problem with "The Invasion;" the filmmakers refuse to give the audience any credit, treating us as if we are the alien beings who can no longer think and feel for ourselves.