Of course, the star of this show is Thelma Ritter, who also earned an Academy Award nomination for Best Supporting Actress that year (pssst...she's really the lead. Perhaps she was too short?). Ritter plays the hard-working, hamburger-slinging mother of up-and-coming junior manager, Val McNulty, who has met, through a brief but impressive encounter, socialite Maggie Carlton (also the soon-to-be-ex-girfriend of his moneyed, ne-er-do-well boss, Junior) and proposed to same. Val is sheepish about his origins, because Maggie is placed rather high on the social ladder and his mother. Ellen (Thelma Ritter), runs a hamburger stand in New Jersey. As it happens, a few days before Val and Maggie are to be married, said hamburger joint goes bankrupt and Ellen comes to wherever they are (Ohio?) to live with Val, since he's asked her to a bunch of times, but in one of those "I've got something to tell you" moments when Val and his mother meet, he goes first leaving her without the heart to tell him the business is gone and finds a way to back out of attending the wedding, preferring instead to meet her new daughter-in-law under better circumstances.
Well, some months later after Ellen has earned enough to buy a decent enough outfit (including an $18 hat!) to pay her daughter-in-law a visit, she arrives on the exact day the poor young bride is trying to host a party for 20 fancy people (Gene Tierney, shorts, flaming turkey) and the bride mistakes Ellen for the cook the agency sent round to help. Ellen doesn't want to embarrass young Maggie and puts aside the $18 hat, dons an apron and saves the evening.
I'm just at the part where Ellen is moving into the newlyweds' apartment and Val still hasn't spilled the beans. I think this is the part where Maggie's mother (Miriam Hopkins) comes in and casts aspersions all over the place.
Anyway, I'm going to watch the rest of it.
You should watch all of it.