A policeman goes undercover and joins a crime syndicate in order to bring its leader to justice.
This was pretty good, once you get past the wierdness of Edward G. Robinson being the good guy.
Joan Blondell, Mr. Otter’s Golden Love Object, plays the girl he likes, but there’s not much love interest: this is first and foremost a crime film. Bogie plays the bad guy, and is very bad indeed. And the ending, while predictable, is great to watch.
A good example of the genre, with good actors in it.