For over a year, Philadelphia has been plagued by a serial killer dubbed the Plate Glass Killer by the media. But finally, the police think they've caught a break – a man has been arrested at the site of the most recent murder, covered in the victim's blood. The man taken into custody is Henry Tyder, the scion of one of the most socially prominent families on Philadelphia's Main Line, a family that possesses the largest tracts of real estate in the city. He's also a hopeless alcoholic, frequently homeless and often estranged from his family.
Although Tyder has apparently confessed to the crime, his attorney believes him to be too disordered to be capable of actually committing the crimes and asks Gregor Demarkian, retired head of the FBI's Behavioral Sciences Unit, to look into the case. Gregor, however, has other things on his mind – after having been away for nearly a year without a word to him, his live-in girlfriend, Bennis Hannaford, has returned to Cavanaugh Street. And everyone seems to have seen her but Gregor. While he waits for Bennis to finally appear, Gregor finds himself enmeshed in complex case of the Plate Glass Killer. Specifically, what would have drive Tyder to confess to crimes he was seemingly incapable of committing and, more importantly, if Tyder isn't the killer, then who really is behind the murders of the Plate Glass Killer.