When Dorothy Martin and her husband, retired Chief Constable Alan Nesbitt, are invited to a country house weekend at a lovingly restored old mansion, they expect nothing more explosive than the Guy Fawkes fireworks. Having read every Agatha Christie ever written, Dorothy should have known better, but even she could not have anticipated the terror that is unleashed by an epic storm and the discovery of a body among the roots of a fallen oak tree. Rendered isolated and incommunicado by the storm, Dorothy and Alan need to work out what in the world has been happening at ancient Branston Abbey, but they soon find that their investigation uncovers some nasty surprises.