When they're given credit cards and a brand new mall to play in, Yin and Yang go on a shopping spree. However, as their bills grow larger, so does the trouble they're in. Will the siblings learn moderation, or will they be forced to pay?
Yin and Yang are training hard hoping to get raises in their allowances, only to for them to realize that they don't get allowances. They are not happy about this and want allowances to buy stuff. A businessman comes and offers them credit cards (Ultimoose in disguise). They take the credit cards and he builds a mall overnight around their dojo. The mall and credit cards are all part of a plan by the Night Master. Yin and Yang immediately start shopping and they blow their entire credit limit in 6 hours. They go to the mall owner hoping to get a larger credit limit but he says that they have pay off their debt. The Night Master and Ultimoose reveal themselves and they have to serve The Night Master to pay off the debt. But Yin finds a loophole realizing they have to return all the stuff they bought before the mall closes in 15 minutes. They quickly return all their stuff except for Yin's necklace. Yin burns their contact while Yang realizes they have the money to buy the necklace. Ultimoose still points out the mall is still his until Master Yo shows up and beats him up.
The episode ends with Master Yo giving Yin and Yang an allowance but he takes Yang's away because he didn't learn math. He says he will double Yang's allowance,Yang gets excited only to realize that he has no allowance.
Yang saying "Curse you, Math!"
- When Yin shoots orbs at the guards, her necklace is seen; yet, as she directs the guards in the orbs up and down, her necklace is gone.