As Christmas approaches Florence is at her most beautiful, the narrow streets glittering with lights, and the shop windows dressed for festivity. Celia Donnelly, a hardworking guide, is looking forward to the perfect job: not a tour party she must herd through the city, but organizing a birthday weekend for the young wife of a rich Englishman. But then, one bitter night, the body of an elderly man is discovered in a public park, the chief suspect in a terrible murder committed fifteen years earlier. And instead of celebrating the holiday, the city - and Celia - must revisit one of the most traumatic episodes of its long and turbulent past.