The show aired on CBS Television from 1960 to 1962 for a total of 70 episodes
The series chronicled the adventures of a private detective agency set in San Francisco. Created by Eric Ambler, the program involves the cases of the detective agency called Checkmate, Inc. Anthony George and Doug McClure run the agency which specializes in preventing crimes before they happen from George's (Corey's) stylish apartment, supposedly at 3330 Union St. Sebastian Cabot portrays a Ph.D. college professor whom they employ as an adviser.
The concept was created by best-selling novelist Eric Ambler. Originally intended to be a show about an elite San Francisco detective agency run by a man, his girlfriend and her Professor father, the girlfriend character was replaced before shooting began by young male contract player Doug McClure, thus leaving the Professor character no real reason to be there so he was re-written to be a consultant only. Ambler was unhappy with the changes so he pulled out completely. His credit would remain for all episodes.
Anthony George....Don Corey
Sebastian Cabot....Dr. Carl Hyatt
Doug McClure....Jed Sills
Ken Lynch....Lt. Thomas Brand
Jack Betts....Chris Devlin