Brimstone - Cherie Priest

During the Great War, Tomas operated a devastating weapon - a flame projector that doused the enemy in liquid fire. Having left the battlefield a shattered man, he comes home to find yet more tragedy - his wife has died of flu. Haunted and broken, he dreams of fire. Alice Dartle is a talented clairvoyant. Her fiery nightmares are connected to the shell-shocked war veteran and widower. She believes she can bring peace to him and his wife's spirit. But the inferno that threatens to consume Tomas and Alice was set ablaze centuries ago by someone whose hatred transcended death itself...