Boy, there's two hoodlums in this movie - a man and his girlfriend. There characters are good film noir material - tough, nasty and uncompromising. They are "Whitey Carson" (Biff Elliott) and "Elsa Hammond" (Marcia Henderson).
Note: Henderson was a Broadway award winner taking honors for her role in 1950 of "Wendy" in "Peter Pen." Boy, that's a far cry from the ultra-tough woman she plays in his story!
Speaking of this story, "Det. Frank Ballinger" (series star Lee Marvin) gets tangled up with these two when he goes undercover to try to get Carson arrested. The only way the Chicago police can do that, Frank figures, is if they get to him through his girlfriend. Ballinger does just that, but pays a terrible price. That's all I'll say, as to not ruin things for those who haven't seen this episode. This turned out to be one, tough assignment!!
Two things appear in this story that have already appeared a couple of times in this first series of M Squad: 1 - Frank likes to go undercover and pose as a thug; 2 - Frank is lucky he's still alive. He gets himself into some of the worse jams I've ever seen on TV.