The Cunningham family plans a quiet, old-fashioned family Christmas until Richie discovers Fonzie faces a lonely holiday.

Richie is sick in bed with the flu and is bored with eating soup and doing crossword puzzles. But when his family leaves him alone in the house, pandemonium breaks loose when Fonzie, Potsie, Ralph, and a burglar join him.

Richie, Potsie, and Ralph Malph visit another part of town to meet some girls and find themselves in trouble when the girls' boyfriends show up. Fonzie steps in to save the day.

It's a new experience for Richie when he becomes romantically attracted to an "older woman."