In the year 2021, more than a decade after a deadly virus wiped out everyone over the age of puberty, grief-stricken loner Jeremiah goes in search of Valhalla Sector, a haven his father told him would be the key to his continued survival. Together with his partner, the tough and cynical Kurdy Malloy, and a mysterious character named Mister Smith, they encounter Thunder Mountain along the way, a highly organized clan attempting to rebuild society, if only they can stop Valhalla Sector's attempts at replicating the virus and gaining control of the world.