Romance of the Three Kingdoms ~The Bird in the Cage~

I—am a concubine of a powerful man!? High school girl Yamada Hana finds herself transported to a world resembling the Three Kingdoms through the power of a mysterious book, and catches the eye of Mengde, a hero who holds supreme power over the continent...? Without knowing Mengde's true intentions, she ends up living in his mansion as his concubine, along with other women...