It's the story of a 10-year-old boy who lives in some really remote agricultural village (there are vast stretches of grain fields, through which the 5 or 6 village kids run and play pretty much every day in what I presume is summer vacation, since there is no apparent school) in the Italian countryside of 1978. The kid is playing around and ends up by himself in a remote area ... and he discovers a kid (the same age as him) who is imprisoned in a deep hole in the ground. So the movie is about this kid -- a kid who has no power with the adults around him, no access to the outside police/media/society, and no apparent way to change the world around him -- and his efforts to find out what the heck is going on. Who is this kid? Who put him in the hole? Why did they put him in the hole? Do they ever plan to let him out? If not, is there any way for our main character to get him out of the hole? What will happen to our main character if he does get the imprisoned kid out of the hole? What will happen to our main character if anyone [esp. the mysterious imprisoner(s)] finds out that he even knows about the kid in the hole?
So it isn't a scary movie, a horror movie ... it's a very quiet movie about a child's place in the world, how children relate to the adults around them, the part of childhood that involves disillusionment and the realization that you can't necessarily trust everyone, the innocent belief of children that they can make a significant difference even all by themselves, and -- poignantly -- the drama of adults seeing themselves through a child's eyes and not liking what they see.
It's a visually beautiful film, with lovely cinematography and directing, and I really appreciated the minimalist dialogue. Much of the message, the truth of the movie is communicated through actions instead of words.
Unfortunately, it occasionally reminded me a little bit of the 2008 British/American film The Boy in the Striped Pajamas, which I found really clumsy and overly preachy and terribly predictable. In fact, there was even a scene in I'm Not Scared in which the two boys are looking at each other through a wall, which was very similar to the other film. This movie was a million times better, though, more subtle, more complex, and just generally didn't suffer from the problems that bugged me in The Boy in the Striped Pajamas, so that only made me resent the occasional flashes of superficial similarity all the more. Striped pajamas boy! Get out of my movie!
Still, I recommend the movie, as long as you aren't looking for exciting action, such as what is implied by the movie's poster. This film is more about an Italian 10-year-old running through grain fields for fun than it is about anybody running away from bad guys.