Mr. Gutenberg, the musical director of Carnegie Hall, mistakes a recording of violin virtuoso Laszlo Laszlo for the playing of Benny the Ball, who has just taken up the instrument. He approaches Benny with an offer to perform and Top Cat negotiates a deal for $50,000 for a Saturday night performance at the Hall-an offer that is withdrawn when Carnegie's Board of Directors really hear Benny play. When Gutenberg offers a $10,000 reward to find the true violinist, the gang discovers that it's their neighborhood street cleaner, Laszlo Laszlo.