Case 39 (2009)
The clever plot isn't quite clever enough to keep you going through the whole movie, but almost. And both Renee Zellwegger as the passionate and trapped social worker and Jodelle Ferland as the adorable but mysterious child are quite amazing. Both are actors at the best of their powers, Zellwegger limited only by the role and the writing, which is very good but not quite flexible enough to let her show as many of those perplexed and touching nuances she is so good at (seen equally in "Bridget Jones's Diary" and "Nurse Betty"). But it's possible Ferland has the role of her life here. She's not only playing a precocious child, but is clearly a precocious young actress, bright, expressive, surprising, and not merely cute. By the way she was fifteen when it was filmed, even though she looks and acts, in most ways, like she's ten.
You can't ignore the plot, of course, since this is a plot driven movie saved by two great actresses, not the other way around. And the story is a little bit of a formula with a twist. The twist is good, but it is singular. Eventually we are carried from a personal and social drama with some evil people to a supernatural drama. It's here where things get scariest, but also where things wobble slightly in terms of believability or logic, if logic has any place here. For example, once the antagonist is shown to have really limitless powers of some kind (possibly imaginary), why does this person not have the power to just kill someone out and out? There is dangled the idea that this bad force depends on fear to proceed, but this isn't developed clearly, or maybe you have to see it twice to get.
On the other hand, if you just go with the flow, it's really increasingly scary. There are some scenes, like the woman in the hospital room that turns into a kind of large oven, that are chilling and really well done. Certainly Zellwegger's character is able to find the outlines of logic as she tries to survive by outsmarting the situation, and we're on her side. Eventually it comes to a dramatic climax, and it's pretty exciting. A sleeper, for sure.