After discovering Mork is an alien, Mindy promises to keep his true identity a secret and allows him to move into her attic. However, Mindy's father, Fred, expresses outrage that his daughter is living with a man (particularly one as bizarre as Mork). Fred's mother-in-law, Cora, presents a much less conservative view, and approves of Mork and the living arrangement. Mindy and Cora also work at Fred's music store where Cora gives music lessons to a young black child named Eugene, who becomes Mork's friend.
Mork's greeting was "Na-Nu Na-Nu" (pronounced "nah-noo nah-noo") along with a hand gesture similar to Mr. Spock's Vulcan salute from Star Trek combined with a handshake. It became a popular catchphrase at the time, as did "Shazbot" (SHOZZ-bot), an Orkan curse word that Mork used. Mork also said "kay-o" in place of okay.