Mara and Dann

Thousands of years in the future, all the northern hemisphere is buried hundreds of feet deep under the ice and snow of a new Ice Age. At the southern end of a large landmass called Ifrik, two children of the Mahondi people, seven-year-old Mara and her younger brother, Dann, are abducted from their home and family in the middle of the night. Left in the care of a sympathetic Mahondi woman, Mara and Dann are raised as outsiders in a poor rural village. Eventually they join the great human migration North, away from the drought that is turning the southern land to dust, and in search of a place with enough water and food to support human life.
Trekking through a barren countryside, Mara and Dann discover different peoples and places and survive a series of hazardous adventures.
Mara's mind is as restless as her feet, and she hungers after knowledge and answers to her questions: Who are my parents? Where do Dann and I come from? Who once lived in these ruined cities we find in Ifrik, and when? And why did they disappear? What will we find up North, and where, exactly, is the North? All the while she dreams of water, trees, and beautiful cities, and of gentle, friendly people. Powerful natural forces, indifferent to human life but essential to its survival, determine the course of Mara and Dann's journey. And Mara - with a thirst to learn almost as strong as her thirst for water, and a compassionate, loving nature that survives despite the cruelty of the environment and of human behavior - is one of Doris Lessing's most appealing heroines.