I like the concept: A mirror to our homeworld appears in the skies… and it appears that we all have doppelgangers on this other Earth. Neat-o, if entirely outlandish. What’s even more intriguing is that this isn’t a “let’s send a rocket to the other Earth and explore” sort of action film (though the planning for that is happening in the background) but a “let’s use this as an opportunity to reconsider our lives and what our other selves might have done differently” sort of deeply personal indie film. The problem is, screenwriters Brit Marling and Mike Cahill — she also stars; he also directs — don’t know where to take it beyond that initial premise. Rhoda Williams (Marling) was a teenager on course for MIT and greatness before she caused the terrible traffic accident that killed a woman and her small son and put her husband and his father, John Burroughs (William Mapother: Lost), into a coma. Years later, she’s just out of prison for the deed and he’s wallowing in grief, unable to resume his career as a composer, unable to live any sort of life at all. She goes to visit him, intending to apologize, but gets caught up in an unexpected friendship with him. As a minor when the accident occurred, her identity was kept from him, so he has no idea who she is… so you can see what sort of personal disaster this is barreling toward. The tediousness of the inevitable revelation is kept somewhat at bay by the duplicate Earth looming ever larger in the sky (good thing the law of gravity has been suspended and the proximity of the other planet isn’t ripping Earth apart!), with all the metaphysicality that entails, which ripples through the undercurrents of the delicately realized relationship Marling and Mapother weave for their characters. But I could never get over the nagging sense, all through the film, that I was still waiting for the story to begin — and then, just where the film ends is where it should have taken its first turn, not its stopping point. All the reasons for the science-fiction foundation for the story in the first place come at the point beyond which the film is willing to go.