When a gunman disappears into the Dublin fog, they leave two seriously wounded police constables in his wake. An immediate investigation is launched by Dublin Castle, which soon uncovers the existence of a Fenian assassination squad that has policemen, informers and judges in its sights. With pressure on the Irish administration from an anxious British government, Superintendent Daniel Ryan and his G squad of detectives must run the gang to ground. Through innovative use of eyewitness testimonies, police reports, medical notes and other material, the author casts a magnifying glass on Victorian Dublin - a city in which the footsteps of the assassin are never far away.