Having sold her home, Fred's antagonistic mother-in-law arrives at the Flintstone cave, and Fred tries to play cupid after meeting a rich Texan who is looking for an elderly wife. He invites the man home for dinner, but Wilma becomes suspicious of the would-be suitor.

Fred overhears Wilma on the phone mentioning ""a little stranger"" who will shortly be visiting the household. Assuming that Wilma is pregnant, Fred summon his dreaded mother-in-law. But the ""little stranger"" turns out to be Arnold the paperboy.

With fatherhood impending, Fred promises to become more kind, considerate, and thoughtful. His willingness to change is strechted practically beyond endurance when his mother-in-law shows up to help Wilma during her pregnancy.

Fred's inept efforts at housework during Wilma's pregnancy are worse than no efforts at all, so he sets out to hire a housekeeper, ultimately bringing home a bank robber named Grandma Dynamite, who is in need of a hideout.