An atomic war has destroyed most of human civilization, leaving Earth contaminated with radioactive fallout. In a home bomb shelter surrounded by lead-bearing cliffs, former government scientist GEORGE BRADECK, his daughter ELENA, gardener-handyman HENRY, and housekeeper MARIA have managed to survive. In anticipation of such an disastrous event, Bradeck has stockpiled supplies for himself and his "family".

Stumbling into Bradeck's home are survivors who by chance miraculously managed to avoid both the initial atomic blasts and the subsequent bands of rioters and looters. Among the survivors are luchador (wrestler)/geologist DENNIS, small-time hood VITO and his "moll" OPAL, as well as TOMMY and SARAH, two highschool students.

As the survivors discover, there are two threats to survival they must contend with: the first is a simple question of whether the radioactive fallout will dissipate before the survivors run out of supplies. The second (and more deadly) threat comes in the guise of Vito; his true intentions are that he wants the other men out of the way, so that he can have the women and shelter all to himself.

But as time passes, the survivors discover a third threat to their existence; radioactive mutant cannibal zombies.