Mr. Gutenberg, the musical director of Carnegie Hall (voiced by John Stephenson), 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to perform and Top Cat negotiates a deal for $50,000 for a Saturday night performance at the Hall—an offer that is withdrawn when Carnegie's Board of Directors really hear Benny play.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 (voiced by Leo De Lyon). John Stephenson provides the voices of Mr. Gutenberg, paramedic, his assistant Ralph, and the record store owner, while Leo De Lyon does the voice of Lazlo Lazlo.

While visiting tonsillectomy patient Benny in the hospital, Top Cat falls for the pretty cat nurse, Miss LaRue. T.C. decides to attract her attention by pretending to come down with a rare illness, which will need a lot of nursing care. Don Messick provides the voice of Dr. Dawson, while Jean Vander Pyl provides the voices of Nurse LaRue, and the regular nurse, and John Stephenson, Don Messick & Leo De Lyon also provides the voices of the patients.