In this film, Sandra Bullock plays a wife whose husband dies, at which point her life falls apart. She seems to alternating between days prior to the accident when her husband is very much alive and days after the accident when he's very much dead. The result is that in the days under consideration, everyone around her thinks she's going mad. Only she can work out what really is going on.
It wasn't a great film, but it wasn't bad either. It was just all a little predictable. Nearly everything that you might expect from an "unexpected death film" happens here, which makes it all a little dull if I'm honest.