But even with praise before its release from Stephen King, James Cameron, and Sam Raimi, Frailty never got the audience it deserved (and still merits). This is a genuinely great work of very specifically American horror, with that American-ness expressed in everything from the details of small-town Texas life to the peculiarly literal-mindedness of American fundamentalist Christianity.
McConaughey narrates events to FBI agent Powers Boothe in the (then) present day in order to explain the identity and origin of a serial killer dubbed "God's Hand" who has murdered six people over the past few years. The bulk of the movie occurs in 1979, as McConaughey explains the role he, his brother, and his father play in the history of God's Hand.
McConaughey's widower father, a small-town auto mechanic, rushes into the boys' shared room one night to tell them that one of God's angels has appeared to him in a vision. The Apocalypse is close at hand, and Paxton and his sons have been drafted into the war. Paxton is to find three magical items and, having found them, await another vision that will tell him what to do next.
What comes next is a list of demons Paxton has to destroy (not kill but 'destroy'). But the demons live among humanity and look like people. However, as Paxton has been given their names and the ability to not only see them for what they are but to also see the atrocities they've committed, he can track them down and destroy them. And Paxton's character is convinced that his sons will also gain the ability to see the demons, as God's plan also involves the boys carrying on this new family business.
So clearly Paxton's character is a loon. And the revelation of the magical items -- a pair of work-gloves, an ax, and a length of pipe -- doesn't make him seem any more believable. One son believes him from the beginning; however, McConaughey tells us in the narration, he himself never believed his father, and would eventually either have to find the courage to stop his father's string of murders or at least run away.
Paxton's direction isn't showy, as befits the tone of the material: this is a tale of the normative surface of things under which, in men's minds, swim terrible creatures in dangerous depths. The actual killings are never shown in all their bloody detail; Paxton leaves it to the mind of the viewer to imagine what's happening just outside the frame. There's a verisimilitude to Paxton's depiction of the day-to-day lives of this strange family, a lived-in, working-class aesthetic to the way things look.
Everything would fail, however, without the performances of Matt O'Leary and Jeremy Sumpter as the two boys in 1979. Paxton gets terrific, believable performances from both of them. They anchor the movie. They also present the two sides of the mental conflict going on: one is convincing as a True Believer who loves his father, while the other is equally convincing as a horrified child who also loves his father, and thus finds it difficult to act against him at first.
In the frame narration, McConaughey delivers a subdued, haunted performance, without a glimmer of that RomCom smarm that derailed his career for more than a decade. And as the initially skeptical FBI agent, Powers Boothe also shines. McConaughey's detailed story gradually convinces Boothe's character about the reality of the identity of the God's Hand killer, leading to a strangely convincing conclusion that's been carefully and fairly set up by everything that's been shown and told to us.
In all, this is a great movie of horror and madness and the bonds of family. While much of the film plays out with growing, horrific inevitability, Frailty also presents some startling surprises, including a scene of awful pathos involving the family and the arrival of the town sheriff at the one boy's request. Brent Hanley's script is terrific, and there's an attention to period detail that makes 1979 seem like 1979. Highly recommended.