It is a story about a boy who longs to be understood by parents who choose to watch from the sidelines. The previews made the boy seem like he was just a creepy weirdo, but it becomes obvious quite quickly why he is the way he is. Joshua tells his father that he does not like soccer and baseball. In an attempt to seem open-minded and understanding, his father tells him that it's okay and that he should just do what he wants (without ever asking exactly what it is that his son wants). His mother just doesn't care as long as she's not bothered.
Dark, disturbing, creepy, but occasionally sadistically humorous, events unfold slowly (much to the dismay of people expecting shock after gratuitous shock) proving Joshua to be a far more calm and calculating boy than originally perceived. Jacob Kogan's performance is reminiscent of Haley Joel Osment in A.I. (if that character were a sadistic schemer). He is the only character who stands out and I believe this was intentional; the other characters can tell, right along with the audience, that the boy ain't quite right.
This movie is certainly not for the impatient and/or those who need to be smacked in the face repeatedly to stay awake during movies. But if you want a movie that slowly and coolly toys with your mind until the very end, Joshua will likely deliver what you are looking for.