Walter Yost is a highly acclaimed composer and conductor of classical music who records on the same label as the Partridge Family. He's heard the Partridges' songs on the radio and finds them charming. When Reuben Kincaid, who used to date Mr. Yost's maid, finds out that Mr. Yost is appearing in San Pueblo as a guest conductor, he decides to invite him to the Partridge house to give his honest opinion on Partridge's First Concerto for Cello in D Major. Mr. Yost listens to the recording, but instead of saying what he actually thinks of it, he asks Keith Partridge what he'd do if he said he didn't have talent. Keith says that he'd quit. Mr. Yost tells him that he doesn't have the dedication to succeed as a classical composer. He also tells him that there's nothing wrong with writing "simplistic" pop music and that making people happy is important. Mr. Yost attends the Partridges' next concert, as does Rachel Westing. During the performance, Mr. Yost tells Rachel that the music accomplishes what it sets out to do: making people happy.