J. B. Stephens

After learning that the head of their community of Novo Mundum wants them killed, five teenagers escape into the Big Empty--a lawless space left desolate after a virus destroyed much of the human race.

Having survived their escape from Novo Mundum, five teenagers realize that they must return to that community to stop its leader from releasing the deadly Strain 8 virus into the world.

Having survived the Strain 7 virus that killed much of the human race, six teenagers settle in Novo Mundum, a hidden city where people are reviving science and the arts, and search for a traitor who threatens to betray their community.