The episode opens on Metropolitan Stadium, where people from all over the world pour in to watch "The Fight of the Century!" In one corner, fighting on behalf of the children of Earth, is our hero Underdog! In the other corner, a large feline named Overcat.
A trillion miles out in space, the planet Felina is suffering from a chronic milk shortage! The cats find all of the milk wells empty. The leader of the planet, Overcat, asks the mechanical brain for an alternate source of milk. The large computer informs the tyrant that the closest planet with milk is Earth. On Earth, milk does not come from wells, but from animals. The animals most popular with milk are called "cows".
Overcat orders his footcats to ready a rocket trains to transport all of Earth's cows to Felina. Each train vacuums up cows from farms, dairies, and the wild. What will the Earth do without milk?