Overview:

Mickey runs radio station ICU from his barn. His friends play various musical numbers. A cat wanders in and starts yowling (which sets Pluto, who was listing from his doghouse, off). Mickey puts it out, but it, and several kittens, keep coming back in, playing with the equipment, running through the musicians (chased by a broom-wielding Mickey, who does a great deal of damage himself), and generally making a mess of things.