Jack Dwyer, Chicago. based ex-cop and sometime actor, is working as an investigator for American Security, a job that brings him to the trendy, expensive Avanti nightclub. Richard Coburn, one of the owners, wants him to find out whether an intruder could get into the club from a back alley--despite all the obvious precautions. Coburn is not forthcoming, however, about the reason for his concern. Then, two days later, he's shot to death in the restaurant parking lot. Coburn's gorgeous wife Deirdre hires Dwyer to find the killer, even though minor employee Earle Tompkins has been charged with the murder. Dwyer also meets Coburn's ex-mistress Jackie, who's bartender and a partner in the club. The third partner is suave Tom Anton, whose beautiful teen-aged daughter Mignon is not as angelic as she looks. There are encounters, too, with a Bible-spouting, garbage-scrounging derelict who stays at a homeless shelter nearby. It seems that Coburn, an unbridled womanizer, had enemies. Motives are many, but not until Dwyer discovers the body of chemist Bryan Ingram near Coburn's house does he get behind the bizarre cause of Coburn's anxiety--and the rather feeble motivation for two murders. Some trenchant comments on rotting factories and the plight of the homeless add depth to a tough-sentimenal hero and to an amiable, mildly engrossing story.