Mario is listening to a song on the radio. As it ends, he tells himself how much he loves the song while the radio announcer says what the song's title is. After that, the radio announcer says that the winners of the WACK Home Radio Broadcast Competition will be revealed. Mario calls Luigi over to the table. They learn that they themselves won the contest, and get to speak live on the radio along with The Wonderfully Wacky Willy White.
Later, Mario, wearing sunglasses and a gold-colored scarf, tells Luigi that they should start practicing. Talking into a spoon attached to several pots, they begin. After quite a while, their voice begins to weaken, and Luigi says that they should probably stop. Mario convinces him that they must continue so as to impress The Wonderfully Wacky Willy White. Luigi turns the radio back on and they learn that he will arrive at 9:00 a.m. the next day.
When Willy arrives at Mario Bros. Plumbing, he starts off by giving his own announcements, then introduces Mario and Luigi. Thanking him, they have too much trouble speaking. He asks them why. They tell him they practiced too much, so that they could make a good impression on him. He tells them that all they had to do was to be themselves, and that he's a "trained professional."
The Pizza Phone rings. Mario answers it, then tells Willy that it's for him. It's his boss. When he hangs up, he tells the Bros. that they are now hot new deejays called "The Whispering Plumbers". However, by then, the Bros. are asleep. Willy then announces that he's signing off, from the home of The Whispering Plumbers, then he calls them "The Sleeping Plumbers". Saying good-bye, he turns off the "On-the-air" sign.