The earth's climate has changed; the northern hemisphere has succumbed to a new Ice Age. In Africa, now known as Ifrik, two children, Mara and Dann, set forth on an odyssey towards the greener country on the chilly southern edge of the Mediterranean.
Seven year old Mara finds herself looking after her four year old little brother while scarcely being able to look after herself. Hunger, dirt, thirst and danger are the children's constant companions. Through their long journey they meet huge beetles whose pincers can bisect a child and lizards that can carry off a woman in their jaws, as they pass through settlements and ruined cities. But Mara slowly learns survival - how to dig up yellow roots to make flour, how to milk a half-starved cow, how to avoid the giant insects that flourish as drought and flash floods drive human beings into retreat.
Together Mara and Dann trace the patterns of gender and of human love from childhood to sexual maturity. Mara's adventures are female, stories of love, fertility, vulnerabilities and ultimately empowerment; Dann's are darker tales of temptation and sin.
Lessing has created part fairy tale, part tract for out time. It is a compelling, troubling and entertaining novel that, through the remarkable odyssey of brother and sister living in the imagined future, manages to tell us a great deal about the present we only dimly perceive and scarcely know how to value.