The movie gets off to an okay start. Two men exploring an old mine encounter strange sounds, and then the setting shifts to a school where a boy named "Lucas" (Jeremy T. Thomas) appears unfocused and messy. It's only when his teacher, "Julia" (Keri Russell), looks into things that it becomes clear something emerged from the mine—something far more aggressive than what entered it. However, after this initial section, the film descends into a rather standard formula, and while the conclusion is set up well, it feels too obvious, short, and underwhelming. The creature, as portrayed by director Scott Cooper, doesn't get enough attention. Much is left to the viewer’s imagination, which works to some degree; still, people who regularly watch movies like this will likely conjure up more intense scenarios than what we ultimately see. It isn’t a bad movie—the pacing is alright, and the young "Lucas" does a pretty good job of carrying it—but there's just not much substance for anyone (or the monster) to sink their teeth into.

Source on TMDB