When a mixed group of Amreican and Chilean youths travel to a remote island in Soputh America, they soon lose their equilibrium - indeed, we're pretty much in 'Blair Witch' territory here, as panic descends in spite of the absence of any explicit external cause. Some people may inherently dislike watching a movie full of squealing teenagers, but director Sebastien Silva shows some skill here, as the innate tensions among the characters drive the increasing deterioration in their mood and well-being. In fact, I really liked the beginning; the end (in which something must, inevitably, be conjured out of nothing) feels a little more random, and insufficiently grounded in what went before.