Richie enters Arnold's in a red devil suit. Arnold's now has an espresso machine, and Al offers Richie a cup. Richie is dressed up for a Dante's Inferno party at the sorority house, and everybody has to dress as a character from hell. Ralph comes dressed as a dentist, and Potsie as "Bluebeard" (with an actual blue beard). Chachi wants to go to the party, but the guys say that it's for grown-ups. Chachi says that he is grown up, and Ralph says Chachi should get Richie to buy his soul. Lori Beth comes in dressed as Lady Godiva. Chachi asks Al for an espresso, but Al tells him that he is too young to drink coffee. Al leaves with a woman named Germaine and asks Chachi close Arnold's up. Chachi says it's not fair that he is too young and is left out of everything. He says he would sell his soul to the devil to be more grown up. Melvin Scratch (the nephew of the devil) mysteriously appears in a cloud of smoke and has come to buy Chachi's soul. Chachi isn't interested, so Melvin tries to convince him that he really is who he says he his. Chachi says he likes redheads and receives a call from Lisa and Linda (both redheads). Chachi signs a contract. Melvin says Chachi is now a warm and wonderful person who is adored by everyone. He tells Chachi to go to Inspiration Point to collect his redheads. Back at the house, Joanie has a new, nearly-$50 dress and is going on a date with Chachi. They all think he is a warm and wonderful person. Chachi comes in, and Joanie, Howard, and Marion gush over him. Richie comes in and tells Chachi that the fraternity wants him to join even though he's still in high school. Fonzie comes in and joins in on the worshiping of Chachi. At Arnold's, Fonzie apologizes for being in "Chachi's office." Chachi explains to Fonzie that he sold his soul to the devil. Chachi has to slap Fonzie to snap him out of calling Chachi a "warm and wonderful person." Fonzie talks to Melvin who pops around in the office. Melvin says if Fonzie can go 24 hours without a girl's lips touching him, Chachi goes free. Otherwise, both Chachi and Fonzie will go down with the devil. Later, Fonzie tells Richie about the deal he made with Melvin. Cleopatra appears, and Fonzie is able to resist her. Richie meets Melvin. Melvin makes Mata Hari appear. Fonzie, with the help of Richie, resists her. Then, Salomé does the dance of the seven veils. Cleopatra and Mata Hari reappear, and Richie sacrifices himself. Just as Fonzie is about to give in, Random the Angel appears and turns the girls into Potsie, Ralph, and Al. Random says he's got reservations for Fonzie and Chachi in Heaven and that Richie may be an angel one day. Random leaves for some harp lessons. At the house, Fonzie is in the last seconds of his "virus," and Marion kisses him on the forehead. Melvin comes to take Fonzie and Chachi. Melvin's magic doesn't work because, according to Fonzie, the only thing that can beat the devil is love. Al wakes Chachi up at Arnold's. Richie comes in wearing his devil costume and invites Chachi to the sorority party. Chachi declines and tells Richie that he is in no hurry to grow up.
Songs in this episode:
"Everybody's Somebody's Fool" by Connie Francis (1960)
"Devil Or Angel" by Bobby Vee (1960)