In Edwardian England a vow of friendship is a thing of innocence. Even when tested by the passionate militancy of the suffragette movement or the rigorous demands of the Season, the bonds between Rory, Eleanor, Jenny and Francesca hold fast. But nothing can withstand the unprecedented onslaught of the First World War - and as the best of an entire generation is extinguished on the battlefields of Europe, a schoolgirl pledge, too, lies broken…