Absolutely nothing happens in this sloooow, annoying, thrill-less thriller directed by Amenabar's usual collaborator Mateo Gil. The film, which in some way deals with the effect of boredom and the quest for thrills, actually delivers none, and seems like an exercise in boredom. The only mildly suspenseful moment is the movie's climax, which takes about 30 seconds of the whole agonizing 100-plus minutes, and is resolved too simply. The plot lacks sophistication or credibility, and while the idea is original, the way the story unfolds is arbitrary and every plot device or twist is a result of outside interference (deus-ex-machina). The hero is always passive, everything happens to him without forcing him to show any initiative or resourcefulness. If you're fans of the genre, watch "Tesis" instead.