"They all crossed into forbidden territory. They all tampered with the laws that lay down who should be loved and how. And how much."

The year is 1969. In the state of Kerala, on the southernmost tip of India, fraternal twins Esthappen and Rahel fashion a childhood for themselves in the shade of the wreck that is their family. Their lonely, lovely mother, Ammu, (who loves by night the man her children love by day), fled an abusive marriage to live with their blind grandmother, Mammachi (who plays Handel on her violin), their beloved uncle Chacko (Rhodes scholar, pickle baron, radical Marxist, bottom-pincher), and their enemy, Baby Kochamma (ex-nun and incumbent grandaunt).

When Chacko's English ex-wife brings their daughter for a Christmas visit, the twins learn that Things Can Change in a Day. That lives can twist into new, ugly shapes, even cease forever, beside their river....