It's summer 1922: Jack Haldean, crime writer and former Royal Flying Corps pilot, is enjoying the village fete. But then, one of Jack's fellow officers is shot in the fortune teller's tent and another ex-colleague found dead at the local pub. Jack soon realises that the roots of the crime go back to the Battle of the Somme when a group of British soldiers were betrayed, ambushed and killed in the tunnels beneath the Augier Ridge. Once again, he must face a deadly enemy.