'The end of the old world' people said about the long hot summer of 1914. It was the last season of optimism, of certainty about the future as the sun set on the Edwardian age. That summer Aunt Tilly comes to stay with her brother the Rector and his four lively daughters in the sleepy Sussex village of Ashden. Aunt Tilly's visit sparks off a chain of events which threatens to split Ashden apart, in which Agnes Pilbeam, the Rectory palourmaid, and her sweetheart Jamie find themselves bewilderingly caught up. Then in August the lamps go out all over Europe and war bursts open the straitjacket of rural village life. The war will bring tragedy, change and love as private torments and struggles are subjected to the greater need. The challenge will prove too much for some and the making of others.

March 1915. Caroline Lilley's fiancé, Reggie, is away at the Front and Caroline gives up her job and returns home at this request. Frustrated in her desire to help the war effort, she throws herself into saving the harvest by organising the village women - and runs up against Reggie's mother, the formidable Lady Hunney. Caroline's sister Felicia departs to become and ambulance driver on the Western Front and Phoebe and George eagerly await their chance to leave the Village. The mood in Ashden changes as it becomes apparent that this is going to be a war unlike any other.

By the summer of 1916, there is still no end to the war in sight and in the Sussex village of Ashden, as elsewhere, optimism has given way to stoicism. In the year that follows, bereavements and shortages take their toll on village life, and at the Rectory the four Lilley sisters each find their own way of contributing to the war effort, while their brother George joins the Royal Flying Corps. Gradually coming to terms with her broken engagement to Reginald Hunney, Caroline Lilley numbly continues with her agricultural work at home, until tragedy forces her into leaving Ashden. Unexpectedly plunged into the fascinating and often frustrating world of military intelligence, she also finds her personal life re-emerging when she renews her contact with the enigmatic Belgian liaison officer Yves Rosier. But how can she tell if this new relationship is right—and will the war give them the chance to find out?

Christmas 1917, and as the Lilley family gathers at the Rectory in the Sussex village of Ashden, the mood is far from festive. But while the sisters face heartache and the new year brings fresh tragedy, the Rectory opens its doors to a new world, its inhabitants strengthened by the grief and happiness shared during the long years of war.