The best thing about this gonzo thriller, the directorial debut of actor Bill Paxton, is its portent-filled title. Your mind automatically precedes it with the word "human," dragging along a cartful of emotional baggage. The second- and third-best things are: the delicious inevitability with which the movies first two acts play out; and the brooding palette of shadows that paints most of its scenes. Paxton is terrific as the widowed father of two school-age sons; he turns on a dime from loving and reasonable to thinking God wants him to destroy demons hiding among his neighbors in rural Texas, circa 1979. Unfortunately, screenwriter Brent Hanley relates the tale via the possibly un-reliable flashback narration of one of the now-grown brothers (Matthew McConaughey, working overtime to be creepy), unburdening himself 20 years later to an enigmatic FBI agent (Powers Boothe, always naturally creepy). The creaky hinge on which the plot finally swings makes Frailty, by its end, seem both clumsy and convoluted.