Bob and Larry approach Pa's store, when Larry notices a flier advertising the annual Karaoke Contest, with the prize being a brand new karaoke gumball machine. Larry is willing to enter again, while Bob isn't so sure, saying that it's a chance to embarrass himself, remembering how he was too nervous to perform in front of everyone the previous year. Larry's act is that he'll gargle and yodel at the same time, with Bob telling him that that's what he did last year, but Larry reminds him that this year, he'll be using root beer, while last year, he gargled purple berry tea, and the year before that, he gargled hot chocolate. Bob then says that he just don't know what's wrong, that whenever he gets on stage, he just gets too scared, while Larry tries to comfort him. At the home of Bob and Larry, Larry is practicing his gargling and yodeling act, when he, Bob, and Junior see an advertisement on TV for the new Tom Celeriac movie "Not Without My Mustache", before Tom Celeriac then advertises Mustache Frosting, which allows people to grow a mustache. Once Bob sees this, he realizes that this is what has been missing from his life, which is a mustache, so he decides to send away for some Mustache Frosting.
Later, Larry is ready to go to bed, asking Bob if he's going to bed, but Bob tells him that he's waiting for his package to come, explaining that he wants it to be ordered as soon as possible. Larry then goes off to bed while bidding Bob good night, as Bob still continues eagerly waiting in front of the door for his package to come. Soon, Bob then goes to sleep where he has a dream where he is approached by Tom Celeriac who tells him that with a mustache, he will fear nothing, before Bob then goes on stage while performing in the Karaoke Contest. After Bob finishes, Pa Grape awards him with the karaoke gumball machine, before Bob then wakes up after that, realizing that it was all just a dream, just as the doorbell then rings. Bob then goes to answer the door, where he receives the Mustache Frosting that he sent away for the previous night. When Larry asks Bob what's going on, Bob tells him that he's growing a mustache, which he proceeds to do after using the Mustache Frosting. Larry is amazed when he sees Bob's new mustache, before Bob tells him to call him "Mustache Bob".
Bob and Larry then arrive in town, while the other veggies are amazed when they see Bob's new mustache. Bob then looks over to see Laura about to fall over while riding on her bicycle but he is able to save her before she could get seriously hurt. Soon, it is now time for the Karaoke Contest, as Larry is seen doing his gargling and yodeling act. After Larry finishes his act, Laura is next up to perform a song called "Shine, Shine, Shine". Backstage, Bob is all hyped up to do his act, while Madame Blueberry asks him if he's alright, with Bob telling her that it's a great day for winning. Soon, it is Bob's turn as he starts to sing about how he is a tomato, which wows everyone in the audience. Unfortunately, while he is singing, the microphone he is singing into accidentally snags his mustache, completely removing it from his face, which surprises everyone, before they start laughing at Bob. When Bob is confused about why everyone is laughing, he realizes in horror that his mustache has been removed before he flees in shame after that, which Madame Blueberry witnesses. Pa Grape then says that Bob's act really had it all before introducing Madame Blueberry to sing the blues. However, Madame Blueberry decides to take a raincheck, so because of that, Pa then introduces Jerry Gourd and the French Peas, who are to sing a barbershop rendition of a song called "Hamsters Have No Love For Ham, But I Love Hamsters Still".
Outside of Pa's store, Madame Blueberry then meets up with Bob, who is still embarrassed about what happened. Bob then asks Madame Blueberry if she's supposed to be singing, but Madame Blueberry tells him that she'd rather be out with her friend. Bob is still frustrated that he can't perform on stage without a mustache, to which Madame Blueberry then asks him if he really thinks that he's incomplete without a mustache. When Bob answers that he does, Madame Blueberry tells him a verse, which is, "Psalm 23:1, the Lord is my shepherd, I lack nothing", before asking Bob if he knows what it means to lack nothing. Bob then correctly answers that it means that if God is with him, then he doesn't need a mustache, which Madame Blueberry confirms. Bob is still unsure about performing on-stage in front of everyone, but Madame Blueberry tells him that she'll sing with him, which makes Bob feel a lot more confident. Back inside Pa's store, after Jerry and the French Peas have finished their act, Pa then explains that the judges are about to tally the votes, before Bob and Madame Blueberry return, with Madame Blueberry telling Pa that she and Bob are going to perform a duet, which Pa consents to. Soon, Madame Blueberry and Bob then perform a rousing blues number about how the Lord is our shepherd and that we lack nothing, before Larry, Laura, Jerry, and the French Peas also join in the song as well, which wows everyone in the audience.