Instructions for a Heatwave by Maggie O'Farrell

London, July 1976. It hasn't rained for months, and Robert Riordan tells his wife Gretta that he's going round the corner to buy a newspaper. He doesn't come back. The search for Robert brings Gretta's children - two estranged sisters and a brother on the brink of divorce - back home, each with different ideas as to where their father might have gone. None of them suspects that their mother might have an explanation that even now she cannot share.