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.
While George Lilley leaves the Rectory to join the Royal Flying Corps, each of his four sisters finds her own way of contributing to the war effort. 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.
Plunged into the fascinating and often frustrating world of military intelligence, Caroline attempts to rebuild her personal life. She renews her contact with the enigmatic Belgian liaison officer Yves Rosier, but how can she tell is this new relationship is right? And will the war give them the chance to find out?