A country house weekend in rural Cornwall ends in murder and mayhem for crime-writer sleuth Donald Langham and his wife Maria. "It's time to let bygones be bygones. Water under the bridge, right? What happened ... happened a long time ago." When Langham's literary agent receives a cryptic letter inviting him to spend the weekend at the grand Cornish home of successful novelist Denbigh Connaught, Charles Elder seems reluctant to attend. What really happened between Elder and Connaught during the summer of 1917, nearly forty years before - and why has it had such a devastating effect on Charles? Accompanying his agent to Connaught House, Langham and his wife Maria discover that Charles is not the only one to have received a letter. But why has Denbigh Connaught gathered together a group of people who each bear him a grudge? When a body is discovered in Connaught's study, the ensuing investigation uncovers dark secrets that haunt the past of each and every guest - including Charles Elder himself ...