This story was based on an episode that was not aired on TV and a script which was officially provided by Toei and was released in 2001 after Kamen Rider Kuuga's full televised run. The oneshot takes place in between Kamen Rider Kuuga's Episode 22 and Episode 23.

After the death of the tyrannical emperor, the empire of Koku (Ke) was plagued by a strange disease caused by a poisonous plague. The only person who can cure the plague is Tsai Feirin (Cai Hui Ling), the last descendant of the Hakutaku (Bai Ze) family, who is known to be able to cure all kinds of poisons. In order to avoid execution, Feirin, who is also the daughter-in-law of the previous emperor, works as a food doctor in the imperial palace, curing one illness after another, which even the doctors are reluctant to treat! A poisonous plague swirling in the palace. A unique doctor of food "conquers poison with poison"! The Chinese imperial palace x medicinal food fantasy begins! https://www.cmoa.jp/title/308732/