Mr. and Mrs. Jones hear a piano being played in their living room. They automatically assume it is their cat who is making the music, when in fact, the talented one is a mouse whom the cat has forced into being his stooge to make him famous. The cat is showered with media attention and set to play at Carnegie Hall, where he hopes nobody will notice that he is pantomiming the movements with the keys while the mouse is playing his miniature piano inside the full-scale model.
A mechanical brain is programmed to sabotage the government's secret lab while working on the first space station.
Dance teacher Miss Placement is dismayed to learn that the head of the School of Ballet where she teaches has entered her beginners class in a contest just three weeks away. But she manages to get them ready and they are a huge success. The school owner is so pleased that he enters all of the school's 1400 students in a contest where they have to learn "Swan Lake" in just two weeks.
Ollie loves to play the tuba but his playing upsets all the people in town. He goes to the country and disrupts the milking habits of the cows. He finally takes a boat and practices at sea in order not to disturb anyone. His tuba-playing saves a ship from going on the rocks and he becomes a town hero.
Sylvester Cat finds that his people have gone on vacation and left him alone in a locked house with a large stash of canned food in a cupboard. Sylvester needs a can opener, or he'll starve. And a pesky mouse has the only can opener in the house and torments Sylvester into trying more and more desperate measures to obtain it.