Whoa! Fonz & the Happy Days Gang wind up in ancient Greece and encounter Umbra, a Medusa lookalike, just when Cupcake (Didi Conn) thinks she's finally figured out how to bring the boys (Henry Winkler, Ron Howard, Donny Most) home. Leave it to Mr. Cool (Frank Welker) to screw things up.
"Greece is the Word", of course, is a play on "Grease", which Conn appeared in 2 years earlier.
Yes, that is also Frank Welker as our announcer bringing us back from the first commercial break. This video is a rerun from when the show was merged with Laverne & Shirley in the Army the following season.
You ever get the feeling Cupcake was just more than a wee bit jealous, giving away what feelings she had for Fonzie?