About to executed by the forces of the Antichrist, a fundamentalist Christian guerrilla is rescued by an Antichrist agent pretending to be a double agent for the Believers' Underground. The agent hopes to trick the Christian into leading her to the dissidents' hidden base. Meanwhile, Armageddon and the Second Coming draw nigh.

Third and best known entry in the Mark IV series of fundamentalist apocalypse films. Fundamentalist Christian guerrilla David helps condemned dissidents escape, attempts to subvert the computerized Mark of the Beast, and generally tries to survive as prophecy unfolds in the rise of the Antichrist to the pinnacle of his power and the beginning of God's war on sinful man.

Patty is lying awake one night in a church basement, distraught and scared. She is to be executed the next morning for refusing to take the Mark of the Beast. Patty knows what lies ahead if she takes the mark but can still not believe in Christ.When those around her try to comfort her and encourage her to accept the Lord, she lashes out at them.