In San Diego in 1918, as deadly influenza and World War I take their toll, sixteen-year-old Mary Shelley Black watches desperate mourners flock to sǎnces and spirit photographers for comfort and, despite her scientific leanings, must consider if ghosts are real when her first love, killed in battle, returns.

Serving humanity with a powerful singing voice that members of her faith believe channels the word of the One True God, Gelya uncovers a deadly military conspiracy before her possession by a demon spirit turns her loved ones against her.

Josie and Alec, who are both twelve years old and live in the same room a hundred years apart, connect and become friends, but when Josie and her sister have problems, Alec wonders if he can change the past and help them.

In his sixth adventure, something sinister is afoot in the house in the west of Ireland in which young Sherlock is staying.