A princess has been plagued by a noisome body odor since birth. The emperor decrees that whoever can cure her loathsome disease can become her royal consort. An amateur aromatherapist, Shum Mong Kai, is given three months to find the cure for the princess. Kai bumps into a fishmonger called Heung who also has a bad body odor. Together, they start their journey to make the cure for the princess.