Another Earth (12A)

Mike Cahill's thoughtful drama drags the ghosts of two recent movies in its wake. First Rabbit Hole, in which a teenage drunk-driver makes reparation with the parent (Nicole Kidman) whose child was run down; second, and more startling, Lars von Trier's Melancholia, in which a new planet pops up to glower down on Earth.

Brit Marling plays Rhoda, a young woman who's done jail time for her part in a car accident that killed a mother and child. Benumbed with guilt, she bluffs her way into the life of the bereaved husband (William Mapother), a composer-turned-bedraggled recluse with no plans to forgive ("I was afraid what I would do to that kid," he says, little suspecting that the culprit is in front of him). Meanwhile, the sky shows a duplicate earth hovering in the distance, apparently inhabited by our own doubles.

Cahill and co-writer Marling use the phenomenon as a springboard for existential teasers such as: what would you say if you met the "other you"? The conceit is somewhat over-extended by the launch of a public competition – a 500-word essay could win you a flight to "Earth 2", as it's called – seeming merely to reheat the old Hollywood chestnut of what-ifs and second chances. Marling and Mapother are very good as penitent martyr and depressed victim, their relationship a timebomb ticking down to revelation, but the sci-fi premise keeps bumping on the doorways of credibility.