Yin and Yang tell Yo that he is old, and Yo makes them pick up his medication. Yo throws a party to look cool, but Yin and Yang make Yo's old enemy, Kraggler, mad. Kraggler turns everyone, except Yin and Yang, into old people.

Yin and Yang get into a fight while cleaning their room, and when Yin costs Yang the world record at a video game, he refuses to shower until one of them cracks and apologizes. But Yang is soon encouraged to clean himself up when his odor attracts the amorous advances of Malodia the Elephant, Princess of the Stink Aardvarks.

Yin and Yang use Zarnot to boost their popularity by lying. When Zarnot becomes huge, they must prove that they are telling the truth.

Yo tells Yin to go to the valley of the two-ni-corns and find a rainbow mane The Gnu to fix her toy. Meanwhile, Yang is taken over by Ultimoose.

Master Yo shows Yin and Yang that black-and-white films can be scary.

A new master is in charge.

Yin and Yang meet the legendary Woo Foo twins.

Shaggler turns into a baby.

The Night Master plots to kidnap Master Yo so he can plunge the world into darkness and be free.

Yin and Yang are magically stuck together by Mastermind so they will learn to cooperate with each other.

Yin and Yang want to become bears, but an evil ranger tries to get them mauled by the animals.

Zarnot creates a robot girlfriend for himself.

Eradicus creates a monster that gains power by consuming everyone's fears, and Yin and Yang try to destroy it.

Yuck causes Yin and Yang to swap personalities so he can weaken them and seize power.

Yin and Yang's dirty-laundry pile turns into a monster and escapes into town.