I'll Be Waving As You Drive Away (1) - S4-E21
Factual error: This episode takes place just after Grace was born (1877). Mary would have been 12 during this time frame, but she is portraying a 15-year-old.
Little House on the Prairie (1974)
1 mistake in I'll Be Waving As You Drive Away (1) - chronological order
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: Peter Billingsley of "A Christmas Story" plays Gideon in this episode. This was his television debut at age 11.