Everyone gathers at Arnold's to have a surprise birthday party for Fonzie. They turn out the lights, and everyone shouts "happy birthday" to him as he walks in. Marion reminisces about the time they showed the apartment to Fonzie's grandmother. Howard tells how he enjoys his quiet evenings, and more clips from previous episodes are shown. They share more memories like when Fonzie teaches Richie the secret of being tough: intimidation. Fonzie recalls the time when he and Richie went to the supermarket and about when they went out with Laverne and Shirley. As Joanie is dancing, Howard and Marion remark how grown-up she's become. Clips are then shown. Potsie tries to start the jukebox like Fonzie is able to do. More Fonzie clips are shown. Fonzie leaves for the bathroom to comb his hair, and Ralph talks about Fonzie's weirdest girlfriend: Richie dressed as a girl for a dance. Fonzie thanks everybody and blows out the candles on his cake as the episode concludes with some "sit on it" clips.
Songs in this episode:
"Little Darlin'" (instrumental) by The Diamonds (1957)
"Hound Dog" by Elvis Presley (1956)
"All Shook Up" (instrumental) by Elvis Presley (1957)
"My Prayer" (instrumental) by The Platters (1956)
"I'm Walkin'"(instrumental) by Fats Domino (1957)