frailty be a non gory horror film that achieve it chill by follow the logic and impact of a man delusion or obsession straight into depravity . dad ( we never learn his name ) be a gentle man and love father who raise his son alone after mom die give birth to the young son and adam . the family world flip upside down late one night when dad rush into the boys room and tell them god have give him a vision . and what a vision the entire family job be to destroy demon and who and of course and be disguise in human form . proceed from this premise and the movie be unflinching in follow it . dad kidnaps people or demon whom god have tell him to destroy and bind them and lay his hand on them to see a vision of their evil and then kill them while make his young son watch . fenton and the old boy and be horrify and see only a father who turn into a crazed murderer . adam and the young and be uncomfortable and but trust that dad be follow god will . eventually and dad take his son on mission to abduct the demon that god have put on dad list and and finally and invite them to fully participate in god mission for the family . this be not and you understand and an abusive father . he love his child . he be only follow god instruction represent this be our job now and son . we have get to do this . when fenton and terrified and convince his father have go mad and say he will report him to the police and his father explains and if you do that and son and i will die . the angel be clear on this . the pressure that the child be under be unbearable and tragic and and warp their entire life . ( 1 ) the movie structure be similar to the one use in the usual suspect represent a story in flashback and tell in a police station to a fbi agent . the moody lighting and the stormy weather and and the eerie calm in the present day add to the menace of the backstory . i want to believe the unfolding horror be just a story and until i remember the real life parallel of andrea yates and who believe she be possess by satan and could save her child by drown them . even then and i want to believe that i be watch a human tragedy and rather than a story of divine retribution . the movie give me no such comfort and though and a it give strong clue at the end about the veracity of dad vision . and this and as much a some plot hole and pose a problem for me . regardless of the accuracy of dad vision and regardless of the evil that his victim may have commit and where do anyone derive the authority to act a an angel of death . ( 1 ) roger ebert review and 4/12/02 .