On the last evening of a Caribbean holiday in February 2019, Connie and Matthew Shaw receive an email from Bella Melrose saying that her husband, Tim, is dead. Time rewinds to the summer of 1976 in Oxford, where the friends first met before becoming couples. Tim and Matthew, both geologists, are completing their doctorates before taking up separate careers: Tim in academia, Matthew in industry. While Matthew is having a wretched time in the Australian outback, Bella loses contact with Tim in Ireland. At Bella s request, Connie sets off to County Mayo and finds him. He is in a state of deep depression and living in a squalid hut. Her presence proves to be a healing force and a powerful emotional bond is established between them. The friendship between the four endures and the feelings between Connie and Tim are suppressed. However, manifestations of them appear during joint ventures, including a holiday in Corsica and a conference in Prague. It causes volatile friction, bordering on the murderous, between the two women.