Obsidian Heart Series by Mark Morris

Psychology professor Alex Locke is an ex-convict, forced back into the criminal underworld when his daughter is threatened. After he agrees to steal a mysterious Obsidian Heart, Locke is pursued by unearthly assassins known as the ‘Wolves of London’. Soon he discovers the heart can enable him to travel through time, and while it bestows him with his own dark powers, it also corrupts...

Transported through time to the dank streets of Victorian London, Alex Locke seeks to unravel the mysteries of the Obsidian Heart, the enigmatic object to which his fate is inextricably bound. When a string of grisly murders takes place across the capital, Alex follows a trail that will lead him through the opium dens of Limehouse into the dark and twisted world of the Society of Blood, and ever closer to unlocking the secret of the Heart.

In the final volume of the thrilling dark fantasy trilogy, Alex Locke is transported to World War One London – will he finally discover the truth about the Obsidian Heart?