London 1715. The air is black with soot. The murky alleyways crowded with people. In the shadow of St. Paul's Cathedral there are rumours of a gruesome murder: the victim had been 'be skewered by an arrow right through his heart'. Even in a city where crime is commonplace, this catches the attention of young Tom Marlow. News of the further victims is soon heard, each said to have been pierced by an arrow and left holding an odd illustrated card. Tom is fascinated and repelled by the strange events. When the mystery unexpectedly intrudes into his own life he feels compelled to investigate...