While her mom and Nai Nai prepare for the grand opening of their family's dumpling shop, Yi, along with Jin and Peng, discover that Yi's violin has attracted a magical, bird-like creature, Fenghuang, who needs their help.
Yi and the crew notice that Everest isn't looking too great; the crew tries everything to cool him down, even begging their old foe, Burnish, for help.
An earth-shaking rumble signals the arrival of a new creature, but Yi and Jin butt heads when each is convinced that they're the better team leader; the crew eventually discovers that a massive Sewer Koi is behind the earthquakes.
Jin proudly dons his new doctor's coat around town, unwittingly drawing the attention of a creature named Morty; after a slobbery lick from Morty, Jin turns invisible.
Yi discovers one of Morty's babies still in her building and attempts to juggle her various responsibilities, but it becomes too much and she accidentally "loses" Mini-Morty; Yi enlists help from Jin and Peng.
Peng learns from Nai Nai that it is his "big bad" year on the zodiac calendar, which means bad luck; Peng is skeptical at first but dives headfirst into learning all he can to secure his spot on the basketball team.
A wish-granting toad drops into Yi and the crew's lives; after granting an abundance of wishes, the toad becomes too weak to continue; Yi and Everest use their magic to reverse the toad's magic so he can wish himself home.
With Yi and Jin tied up in their respective CNY festival performances, Peng and a semi-disguised Everest hit the festive streets, eating and enjoying everything in sight.
Yi realises that Peng and Everest -- along with their other creature friends -- were taken by Nian, the legendary dragon-like creature associated with Chinese New Year.