Estranho Amanhã de Jean Karl . 1985.
This fleshes out the Clordian Sweep alluded to in Karl's The Turning Place (1976) and But We Are Not of Earth (1981). The first half deals with 13-year-old "Janie One," who, through unlikely circumstances, finds herself, her Air Force captain father, and her younger brother in an underground Presidential bunker when an attack from the planet Clord destroys all exposed life on earth--grass, trees, everything. Then, while their father lies in bed in a deep depression, the two children establish radio communication with a few other survivors. Part two, set generations later, takes up "Janie Two," a novice Sustainer setting off from her home cave as part of a program to populate different valleys according to the plans and seed supplies of the earlier Janie's "wiser" generation.