Alex Locke is still searching for his missing young daughter. Transported through time to the dank streets of Victorian London, his only hope of finding her lies with the obsidian heart, the enigmatic object to which his fate seems inextricably bound. Desperately seeking the heart, Alex follows the trail of a gruesome murderer 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 – and finding his daughter.