The Blackwood line has always been inextricably linked with Coldharbour. Since Horatio Blackwood founded the agency, five of his descendants – or perhaps six, depending on how you do the counting – have borne the responsibility of keeping London’s underground horrors away from an ignorant populace. Professor Mary Blackwood is the most recent – and, some might say, the most effective. A shrewd operator, proven in the field and in the smoky chambers of Whitehall, Mary’s dedication to Coldharbour’s work is beyond question. Few in the organisation know her well. To most, she’s a distant figure, seized of a pragmatism bordering on ruthlessness. Some underlings whisper that she’s haunted by the ghosts of the past. Others point to the sealed room in her office – a room to which only Mary has a key – and speculate that her ghosts may be more than figurative.