It is 1852, and Inspector Robert Colbeck and his assistant Sergeant Victor Leeming are faced with their most complex and difficult case to date. As a train speeds over the Sankey Viaduct, a man is hurled from a carriage and plummets into the canal below. It later transpires that he has been stabbed to death.
It was meant to be a harmless stag night prank. A few hours later four of his best friends are dead and Michael Harrison has disappeared. With only three days to the wedding, Detective Superintendent Grace - a man haunted by the shadow of his own missing wife - is contacted by Michael's beautiful, distraught fiancée, Ashley Harper. Grace discovers that the one man who ought to know Michael Harrison's whereabouts...