Gone (2012)

Jill Conroy was kidnapped from her bed and dumped in a pit in the middle of a forest.  She found human remains in the pit with her, and when her abductor came to add her to his list of victims, she stabbed him with a broken shard of bone and escaped.

Unfortunately, there are no signs of forced entry at her home, she has suffered no injuries, and investigators are unable to find the pit.  This lack of physical evidence causes local police to write off her story. This is especially true after Jill is forcibly institutionalised for a time, and then becomes a regular visitor to the precinct whenever another young woman goes missing, claiming that this is another victim of the man who took her.

Naturally then, the police are not terribly interested when Jill claims her sister Molly - who has a history of problems with alcohol - has been abducted.  They consider it far more likely that Molly has gone on a bender and is sleeping it off somewhere.

Just as naturally, Jill isn't willing to accept that answer, and begins her own investigation into Molly's disappearance.

I don't think it is much of a spoiler to tell you that Jill has a better idea of what's going on than the police do, is it?

This film has a very bad rating on Rotten Tomatoes (11% at the time of writing), with most of the complaints centring on the fact that the tension and suspense aren't consistently maintained and that Jill, however right she might be, acts like a crazy person.  I'm not sure the latter complaint is really fair.  I'm pretty sure most of would be somewhat irrational in her situation.  There may be some truth to the former accusation, though I personally quite liked the lower-key approach of the film and the fact that it eschewed the normal two-hours-and-change run time for a more slender 90 minutes.

If you enjoy thrillers, you might find this a pleasant diversion.  I did.