It's the middle of the 21st century, and the next Ice Age has suddenly sent global warming into reverse.
Saul is one of the Ice People, the threatened peoples of the northern hemisphere, who, watching their world freeze over, try to move south towards the equator. 'Set in the near future, it imagines not a globally warmed world, but an earth slowly returning to aridity and cold.
A universal freeze has also descended upon relationships between men and women, who live in morbid segregation, with feathered robots as sexual partners.
In a neat reversal of First World-Third World assumptions, Africa's relative warmth offers a last hope to northerly survivors as the novel charts one man's struggle to rescue his alienated son and bring him to where the sun shines' - Rose Tremain.