Forensic scientist Sean McKinney hunts a serial killer who is targeting senior citizens associated with the 1930s era Barker-Karpis gang. But, getting justice for a wrongfully accused man means bucking the system and putting his life on the line. Will the trail of corpses left by the real killer include McKinney? Part crime story, part historical fiction, A Trace of Gold moves from modern day Chicago to the time of gangsters and gun molls, painting a picture of Chicago crime in two eras.