Kouguu: Itsuwari no Kouhi, Koukyuu ni Haitte mo Otonashiku wa Shimasen

Sui (Hui), a girl who grew up admiring "Shirogane" (Yin) - a chivalrous thief who once disturbed the capital, was secretly learning martial arts from the village elder Li Bo. One day, the king dies and the inner palace was to be remodeled. It was then that a call-up notice for a court lady was delivered to her older sister Kouju (Ang Shu) who was about to get married. Sui decides to take her sister's place and enter her inner palace, but...!?