Bill Robinson wants to get into the show, but the man who owns it doesn't want any amateurs (heh), so Bill wins it and finances it in a crap game, then the entertainers start singing and dancing.
It's one of the several all-Black short subjects that Vitaphone and other short-subject producers turned out. Although they played many theaters, they were conceived as something to offer the Blacks-only theaters of the era; producing a race film (as films starring Blacks in the era were called) was not considered a viable business model, but a short subject was much cheaper to turn out, and the polish that Vitaphone could bring to a production like this was appreciated.
Although I could watch Bill Robinson and his easy-going, self-assured dancing endlessly, the big number is "Got the Jitters" featuring Babe Matthews, the chorus line and some great lighting by Vitaphone cameraman E. B. DuPar.