I know very little about Willie Howard apart from his being popular on the radio because he could do a wide variety of accents. Here, he plays a seemingly stupid detective.
When the story begins, you learn that an heiress has been missing for 20 years. If she's not located, a worthless relative will instead inherit the money. Unfortunately, the private detective agency hasn't been trying to find her, as they are in league with this awful relative. And, to make the client happy, they assign a new man to the case....a guy they assume will bungle the case. During the course of the investigation, the Professor (Howard) pretends to be many different people...including one who is Scottish and another who is Chinese!
So is this any good? Well, the story is very short on laughs, so it's no great comedy. It is, however, a good showcase for Howard as he gets to show off these dialect skills...even if the Chinese one will no doubt give politically correct folks a coronary!