“Never Let Me Go,” an adaptation of Kazuo Ishiguro’s novel of the same name, is about as good as it can be as a two-hour film. The acting is top notch, as is the cinematography and art direction. The story is thought provoking, emotionally resonant and the characters are complex and well rendered. With the exception of a cheesy and superfluous monologue at the end, there isn’t a false note in the whole thing — its problem is really just that it’s too short.

The film — a soft sci-fi/horror tale told as a love story — spans three decades. It follows the lives of Kathy, Tommy and Ruth, from their time as students in a “special” elementary school called Hailsham, through adulthood. Kathy (played as an adult by Carey Mulligan) is a quiet, understated girl. She is in love with a boy named Tommy (played as an adult by Andrew Garfield), a gentle soul, who is quick to become flustered and frustrated. Tommy obviously has feelings for her as well, but he winds up romantically involved with Ruth (played as an adult by Keira Knightley), an outspoken and extroverted friend of Kathy’s.

This love story aspect of the plot is conspicuously similar to just about every Japanese TV drama ever aired (and it resolves itself in a somewhat similar way as well). However, the actors and director Mark Romanek skillfully suggest complex human beings through the characters’ expressions and subtle actions — even when their more overt actions seem soapy.

The film’s aesthetic elevates it as well. The dated stone building that houses Hailsham, where the kids grow up, and the rustic “cottages,” where they spend their adolescence, are surrounded by rich natural beauty that inspires a sense of yearning and gives the film a transient beauty that fits the story and characters perfectly.

What keeps the film from perfection is that it has too much story to fit into the runtime. The pacing, at least of individual scenes, is great. There are moments of suspense, shock and sadness that can only be built up to gradually. Romanek and screenwriter Alex Garland wisely choose not to rush through scenes to get to more story. In not doing so, they keep the viewer engaged and emotionally invested in the film. The trade-off, though, is a sense that we are constantly missing important scenes — for instance, Tommy and Ruth’s courtship is not seen, just explained by a couple lines of narration.

The filmmakers should also be commended for not shying away from some grim themes, one of the best aspects of “Never Let Me Go.” To even begin discussing these themes, though, would spoil the film’s considerable mysteries. If you would rather be surprised, stop reading and go see the film — it’s excellent. Come back and read this after.

If you’ve already seen the film or don’t mind spoilers, here we go: The Hailsham school is actually a special school for “donors” — human beings cloned so that their organs can be harvested. When they reach adulthood, they are to have their organs surgically removed until they “complete” a clever and heartbreaking euphemism that describes a “donor” not surviving surgery.

This concept is incredibly loaded and could be used to make any number of political points. Small government Tea Party types can read their politics into the idea of a society in which the government controls its citizenry to the point of choosing some to die for the benefit of the others. Critics of capitalism can see “Never Let Me Go” as an indictment of a system that sees human worth as limited to the “value” they can provide and a meditation on the existential loneliness of living in such a system. For people who have lost jobs and must scramble for a way to pay for food and housing, for people who have fallen ill and cannot afford health care, and for people who are sympathetic to such plights in a country without a substantial society safety net, there will be a familiar sting in the film — the pain of having to prove what on some level feels like a given: That you are worthy of living.

“Never Let Me Go” smartly avoids politicizing and instead poses philosophical questions that are universal and timeless.

The basic themes are: “How do you prove your humanity?” and “What does it mean to live comfortably off the suffering of others?”

The way characters go about trying to prove their humanity is not terribly different from the rest of us. They observe the “real world” from a distance, through toys and cassettes donated to them and, later, by watching television. Ruth, upon being exposed to sitcoms for the first time as an older teenager, blatantly mimics the shows’ dialogue and their characters’ interests. Her actions probably resonate with all of us, minorities and marginalized groups in particular, but the film’s central premise gives the scene a tragic, haunting dimension and causes us to question our own relationship to media images.

In one scene, Kathy intently flips through pages and pages of a porn magazine, confusing her friends. The reason she does this is another spoiler so, again, if you’d rather not know, stop reading now.

All “donors,” it is rumored, are cloned from people from the lowest levels of the social hierarchy — sex workers and drug addicts. Kathy experiences sexual urges, so she comes to the conclusion that her “original” was a porn model. This scene echoes the minority experience; there is no real reason to believe that Kathy’s sexual urges are at all abnormal, or even that she was cloned from a porn model, but she has so internalized stereotypes about her “people” that she sees her normal biological impulses as abnormal and attributes them, not to human nature or who she is as an individual, but to characteristics of her “race.”

But the desire to prove one’s humanity by understanding one’s roots, as Kathy does, or through artwork, as Tommy does, is also not an endeavor limited to clones.

The love triangle in “Never Let Me Go” also has a philosophical undercurrent. The characters learn of a rumor that by being “verifiably” in love, their humanity will be recognized and they will be exempted from the cruel social and economic system they were born into.

Yet another spoiler: None of these methods of proving humanity work. And while some might see the film’s message as being about how pathetic we are for trying, I believe the real underlying message is much less cynical: we shouldn’t have to prove our humanity.

In the film, though, dehumanizing certain people benefits a large enough sector of society that it may be impossible to stop. To paraphrase one of the “real” human beings in the film, no one even wants to think about whether or not the clones are human, because that would mean “going backward” and giving up the opulent lifestyle the clones afford them — a timely message while we grapple with global inequity, climate change, animal rights and the overall ethics of consumption.

“Never Let Me Go” has proven divisive with critics, with many finding fault with the characters’ resignation. Why, many a reviewer wrote, don’t the characters simply run away? Why do they only seem aware of the unfairness of their lives in sporadic emotional outbursts?

Personally, I found the characters’ lack of resistance completely true to life. They are raised in such a way that the idea of subverting the system never occurs. They only hope to be exempted, to be chosen as being special. And the actors do a fine job of displaying a sense of dread, resentment and self-loathing that only boils over when there is a suggestion that they are not special and will not be exempted.

Ruth, at one point, suddenly becomes incredibly mean toward Kathy. We later learn that she did this because she feared Kathy and Tommy could truly fall in love and that she, Ruth, could not. In the end, she confesses and urges Kathy and Tommy to get together and win deferment of their fate. She is the film’s lone revolutionary — realizing that living on others’ pain is wrong and ultimately empty — but because they cannot see the big picture, neither Ruth nor anyone else sees the larger implication of her sacrifice.

“Never Let Me Go” is a harrowing film and one which will leave you with plenty to think about and discuss.