I was completely enthralled by debut film “Another Earth.” For the first ten minutes. The movie has an intriguing sci-fi premise: What if there were another planet exactly like this one — same people with the same life stories? What if we opened up a line of communication with Earth 2 and put together a team of astronauts to explore it? Alas, the movie does not answer any questions raised, though writer-director Mike Cahill has an interesting way with his camera. I particularly enjoyed a spooky crane shot at the beginning. The movie also heralds a talented new actress in Brit Marling, who co-wrote and co-produced.

Marling is a slender blonde beauty who plays a brilliant MIT student who gets drunk and smashes into another car, wiping out an entire family except for its patriarch (William Mapother), a Yale prof and composer. She does four years in prison then tries to put herself together.

The movie rolls out one Sundance cliche after another. There is the Car Crash That Changes Everything. The Alienated Loner Trying to Find a Place in This World. There is the Unbelievably Beautiful Cleaning Lady (Marling’s Rhoda takes a job as a school janitor). There is the Wise Old Working Class Geezer (a fellow janitor). There is the Cameraman Who Can’t Stop Playing with the Zoom Lens and the Desperately Grappling Sex Scene That Looks Like No Fun at All. And this is one of those movies in which an hour of screen time could be saved if one character uttered literally one (1) sentence to another character: Rhoda tracks down the prof, who has emerged from a coma and has no idea she is the one who killed his wife and kids, and gets herself hired as his cleaning lady, then gradually becomes his confidante and more.

There is no question that Marling has acting chops, showing a great deal of sensitivity and tenderness, though her performance is more or less one-note. One does tire of movies about vaguely stupefied young beauties sleepwalking through a pained life. Moreover, Mapother is an undistinguished character actor who doesn’t hold the screen. And the movie’s prospects should be measured against those of the similar flop “Rabbit Hole,” which was also about a beautiful woman dealing with the aftermath of a Car Crash That Changes Everything and also bruited about the idea of a parallel planet where, maybe, our other selves are a lot happier than we are and, I guess, no one ever suffers from vehicular mishap.