London, 1890. Captain John Hardwick, an embittered army veteran and opium addict, is released from captivity in Burma and returns home, only to be recruited by a mysterious gentlemen's club to combat a supernatural threat to the British Empire.

This is the tale of a secret war between parallel universes, between reality and the supernatural; a war waged relentlessly by an elite group of agents; unsung heroes, whose efforts can never be acknowledged, but by whose sacrifice we are all kept safe.