"The Midnight Lady" is a cheap reworked version of "Madame X" made by itty-bitty Chesterfield Pictures. And, for a movie by this poverty row studio, it's pretty good....even though it's not exactly original. On the other hand, there are better all-suffering mother films...not just "Madam X" but "So Big" and many other films of the classic era....films in which mothers give everything to protect their children who don't even know they exist.
The story begins with a troubled household. Although the family has money, there isn't a lot of love there and it's strongly impacted by the angry and prudish grandmother....who spends much of her energy controlling or trying to control everyone. As for the grown children, they are clearly rebelling against it. As a result, you really cannot like either extreme....the self-destructive rich kids nor their father and grandmother who are prudish and loveless.
What no one realizes is that the speakeasy that the kids frequent is run by their biological mother! Nita is loved by the kids, though she never divulges to them that she is their mother and she apparently left when they were tiny children. Late in the film, someone is murdered and Nita thinks her daughter did it...and so she takes the rap. Is this the end of the story? Nope.
The film is okay....mediocre in practically every way. But it is oddly entertaining and worth seeing if you love weepy self-sacrificing mommy films.