Orson sends Mork on a mission to Earth in his egg-ship to learn about sexual customs. As Mork arrives, Mindy's having a date with the aggressive Tony, whom she performs oral sex on. Mindy gets mad when Tony ejaculates in her mouth, an argument ensues and he leaves with her jeep. Nearby, Mindy stumbles upon Mork, whom she presumes is a priest, not realizing he's wearing a suit backward. After arriving at home, Mindy discovers Mork's not a clergyman, but rather an alien who drinks with his penis.
Little do Mork and Mindy realize that they're being spied on by the Necrotons, two of whom show up at Mindy's door masquerading as traveling dildo saleswomen and seduce her into lesbian delights, while a third brings Mork to their ship to indulge in carnal pleasures.
Mork returns to Mindy's apartment and summons Fonzie (the only man with an appendage more powerful than Mork's) to infiltrate Captain Nirvana and create a harmonious existence between humans, Orkans and Necrotons.
When Fonzie leaves with the four Necrotons, Mork decides to inspect Mindy for the fabled second human vagina, and soon they are carnally embroiled, thus completing Mork's quest to discover the secrets of sexual customs on Earth.