Yang won a doll at the county fair for Yin, but the doll is actually Zarnot.

The Night Master rebuilds his armies that were frozen years ago by Master Yo. Little do they know, Yin and Yang are involved in his plan.

Yin meets a hamster who loves to clean while she is out buying cleaning supplies. The hamster reveals himself to be Fastidious, and asks the Woo Foo students to help him defeat some of the spirits who have been making a mess. However, there is something sinister about Fastidious.

Yang is really interested in a girl named Lina, who is Yin's really good friend. The trouble is, Yang's behavior turns Lina off. So Master Yo suggests that Yang should try to be more like Yin in order to make Lina like him.

A fun road trip serves as a cover for a covert operation.

Information on Yin and Yang is leaked to the Night Master and the twins try to find the culprit.