The Wolves - S4-E5
Character mistake: At one point upstairs (after Mary tells Laura to turn off the lights), Laura tells Mary she's using the moon to see her book - and even the moon itself is shown afterwards. However, this would not be realistically possible as this window looking outside faces north and the moon (as well as the sun) would never shine into that side of the house as neither is ever on the north side of the sky, especially in Minnesota.
Laura: I wanted to clean the blackboards extra good today, to make up for being late.
Mary Ingalls Kendall: And talking in class?
Laura: I was not talking.
Mary Ingalls Kendall: You were, too.
Laura: Was not! Nellie was talking and I was answering.
Trivia: Star Michael Landon was born 100 years after the real Charles Ingalls. Ingalls born 1836 and Landon born 1936. Lindsay/Sidney Greenbush (who played Carrie) was born 100 years after the real Carrie. Carrie in 1870 and the Greenbush twins in 1970.