Imagine if you will ... another Earth, with another you … did that you make the same mistakes? Is she, or he, more successful or happier?

These are the questions Sundance award-winning film Another Earth poses as it beckons you into a modern Twilight Zone. If, however, you can’t stomach sci-fi that’s based on shaky science, it may not be a screen destination you want to visit. If instead, you’re willing to suspend disbelief and a few planetary laws and logical assumptions then it’s a trip worth taking -- and one that will linger long after it's over.

Though director/writer Mike Cahill's film revolves around a fantastic premise -- that another mirror Earth has suddenly manifested itself and hasn’t, miraculously, proved catastrophic for either planet -- it’s kept in motion by the forces of taut, intimate human drama, at the heart of which is Rhoda (the movie's co-writer, Brit Marling). The future looks bright for the beautiful, brainy MIT-bound 17-year-old, until her post-party drunk driving causes a tragic car accident that kills a wife and child and leaves the husband/father, John (William Mapother, Lost's Ethan Rom), in a coma. Four months later, Rhoda, her spirit still hung in shame, is released from jail. Preferring to work with her hands and avoid conversation, she takes a job as a high school janitor. (But she doesn’t secretly solve any unsolvable equations and then get a job at a government think tank, she just mops floors with an old Indian man that looks, and acts, as if he’s occasionally possessed or suffers from schizophrenic fits.)

Things get tricky when Rhoda learns John has recovered; she knocks on his door so she can deliver the heartfelt apology she’s rehearsed. Not surprisingly, she chickens out and instead tells him she’s offering a free trial cleaning service -- an offer he can’t refuse considering the dirty, disheveled, liquor-bottle-littered state of his home. As an unlikely romance blossoms between the two, the truth of who Rhoda is looms above it like a storm cloud. In fact, it looms above the entire film and its landscape. Minus a few blissful sun-meets-sea vistas of Earth's alluringly ghostly twin, it weeps with grief, despair, and regret -- from its gray skies to its somber symphony soundtrack.

But the parallel Earth (and plot) that haunts the horizon also offers a sliver of hope, especially when United Space Ventures announces it will send the winner of their essay contest on one of the first flights to the duplicate planet. Brit’s arresting entry begins “as a felon, I’m an unlikely candidate for most things…,” and proceeds to point out that most explorers have been convicts or madmen.

Meanwhile, to add to Another Earth's surreal atmosphere, Rhoda's story unfolds amidst the background buzz of T.V. and radio sound bites that echo the baffled world’s attempt to make sense of Earth 2, like a subconscious narrative in a dream. The film is also full of arresting ethereal scenes, such as Rhoda lying hopeless and naked in the snow, or John’s unearthly saw serenade.

As forewarned, Another Earth has its logic flaws, and a moodiness that at times borders on melodrama. Yet it’s still the stuff of great science fiction -- intriguing, gripping, and well-acted with the requisite plot twist -- and ultimately, it's unforgettable.

Grade: B+