A pastor and a teacher, two pillars of the small community of Triune, share a dark and unspeakable secret: the common enemy of an ancient demonic terror deigns to destroy one through the other during the Devil's hour.

A giant alien mosquito-type insect is drawn to earth from the CO2 pollution in search of blood. Del, a government agent, loses loved ones to the creature and is on a personal vendetta while the Dr. Kempler is captivated by it and attempts to help the creature cleanse the earth.