The Eccentric Doctor of the Moon Flower Kingdom Vol. 11 (manga)

Now that Keiun has successfully convinced Noah to allow Koyou to stay in the capital, he can finally breathe a sigh of relief. That is, until he hears urgent news from the palace that the empress has fallen mysteriously ill! Fearing the worst, Keiun realises his only option is to send in his trusted secret weapon: Koyou! Disguised as a court lady, the young doctor will need to infiltrate the palace and protect the empress’s life at all costs. Let the secret mission begin!