Agnes Trevelyan witnesses an attempt on Queen Victoria's life. The queen survived, the attacker died on the spot, but Agnes, thanks to her supernatural gift, manages to notice: the would-be killer was controlled by a ghost in a monk’s habit! Only Pastor James Linden, Agnes's guardian, has enough skills to hunt the undead, but they do not even suspect what terrible force is opposing them. The investigation leads first to Bedlam, the famous mental hospital, then to the chambers of the Prime Minister, then to Buckingham Palace. But what goal does the mysterious monk actually pursue and which mortal voluntarily entered into the ghost conspiracy?..