Keira Knightley, Carey Mulligan and  Andrew Garfield play old school chums trying to come to terms with their very dark fates in this sci-fi chiller.

What passes for great science fiction these days boggles the mind. I’m talking about ridiculously over-praised films like “District 9,” “Inception” and “Avatar,” all touted as both visually inventive and socially relevant.

In reality, they’re simply colossal bores, especially when compared with classics of the genre such as “Metropolis,” “2001: A Space Odyssey” and the original “The Day the Earth Stood Still.” Those were revolutionary movies by visionary directors willing to take chances with their imaginations instead of their wallets, ala James Cameron.

The only sci-fi flick to come close to those greats of late was Richard Kelly’s 2001 masterpiece “Donnie Darko.” The rest are ciphers. And, yes, that includes you, Steven Spielberg, and your twin flubs, “Minority Report” and “A.I.: Artificial Intelligence.”

These films get lazier and lazier, as special effects routinely take precedence over insight and ideas. Which brings me to “Never Let Me Go,” Mark Romanek’s faithful adaptation of Kazuo Ishiguro’s cautionary tale about human cloning. It’s the anti-“Avatar,” rich in thought and completely devoid of tricked-out 3-D effects.

Like Merchant-Ivory’s adaptation of Ishiguro’s “The Remains of the Day,” “Never Let Me Go,” is told in expressions and gestures jesters more than words. It’s all about mood, dark and foreboding. Yet, amid the despair, remains a glint of light called love.

In this case, it’s between two girls and a boy, all students at the prim and creepy Hailsham boarding school, located deep in the English countryside, far away from reality.

Romanek and writer Alex Garland sufficiently create a sense of dread that hangs ominously over the school. You feel the sadness and despair down every soulless corridor, especially early on, when we’re introduced to Kathy, Ruth and Tommy as children.

Their realities are as elusive as their futures. They sense there’s a world outside Hailsham’s gates, but they are unaware of exactly what it is and how it relates to them. All they know is what their enigmatic headmistress, Miss Emily (Charlotte Rampling, terrific as usual), tells them, which isn’t much.

With neither parents, nor siblings, it’s almost out of necessity that Kathy (Isobel Meikle-Small), Ruth (Ella Purnell) and Tommy (Charlie Rowe) form an evolving bond that takes them from true friends to something closer to  enemies, as they approach adulthood, and as such, their fate.

I’ll remain mum on what that destiny is, but you’ll probably figure it out long before Sally Hawkins (superb as the kids’ straight-talking teacher, Miss Lucy) informs them they shan’t be needing AARP or 401(k)s.

Let the shivers commence rippling down the spine, as you rejoice in finally encountering a sci-fi flick that has more on its mind than pure dazzle. Now imagine how deflated you feel when a third of the way through the kids transform into vacuous adults played by Carey Mulligan, Keira Knightley and Andrew Garfield.

Not only does the trio look ridiculous in their wigged-out 1980s hairstyles, they act like zombies. I’ve seen plants and trees with more personality, as the three actors struggle to convey what it’s like to be striped stripped of your humanity and raised as a commodity.

Don’t get me wrong, Mulligan, Knightley and Garfield are three of England’s finest young talents, but clearly they haven’t developed the chops yet to act without their voices. It’s deadly, too, as they sleepwalk through their scenes, failing to generate empathy or interest in their character’s unspeakable plight.

The fatal blows, however, are struck by Romanek (“One Hour Photo”) and Garland, who do nothing to address the lingering question of why these kids just don’t make a run for it.

I get that their acquiescence is part of what makes the story so heartbreaking. And I’m certain that their persistent lethargy works hauntingly on the page. But up on the screen, it cheats “Never Let Me Go” of any possibility of generating conflict or suspense.

And without that, there’s nothing to hold you beyond the contrived love triangle involving Ruth and Kathy taking turns seducing Tommy, not necessarily out of passion, but in faint hopes of delaying their preconceived fate. It’s interesting for a while, but Romanek renders the affairs so obtusely it’s hard to make an emotional investment.

The movie works far better as a metaphor for people who never question their existence or challenge their destiny, often out of fear. Romanek is on to something, too, especially in today’s economically challenged world, in which we remain in bad marriages, bad jobs and even bad cars, because we’re too scared of what might happen if we dare make a change. It’s a great message, but too often it gets lost in a film blinded by its own pretentiousness.

Contact Al Alexander at aalexander@ledger.com.