Yin comes down with a case of the Woo Foo Flu, an illness that causes her to bend reality whenever she sneezes. Master Yo orders Yang to take care of her while Master Yo concocts an antidote for the Woo Foo Flu. However, Yin later gets captured by Carl – who intends to exploit her illness so it can help him take over the world – and Yang may have to get himself sick to save Yin.