The Hep Cat opens with a cat (who resembles the one from Notes to You) strolling through an abandoned lot. Unfortunately, he stumbles across a dog named "Rosebud"—otherwise known by fans as Willoughby the Dog—who, upon noticing the cat, gives chase. The cat, after a successful escape, begins singing "Java Jive." Later, the cat encounters an attractive female cat, and attempts to woo her, failing utterly. Suddenly, Rosebud the dog reappears and the chase resumes. After a series of zany, Clampett-esque sight gags, the cat once again evades the dog. As the cartoon closes, the cat can be seen kissing his dream girl—a puppet.