Happy Days (1974)

Episode 157 is Happy Days (1974)

 is an American television sitcom that aired first-run from January 15, 1974 to September 24, 1984 on ABC, with a total of 255 half-hour episodes spanning eleven seasons

Richie Cunningham's dreams seem about to come true when he's invited to babysit with Mary Lou Milligan, a pretty girl with a racy reputation.