From Which Scanlations:

With a boyfriend who's an idol on the rise and a wacky grandfather who has a penchant for inventing and Japanese history, Hana's life is crazy enough. Things get even more complicated when Hana runs into a burning building, trying to rescue her grandfather, and finds herself face-to-face with a man who seems to be a samurai from the past...

Sakura Karukaya liked her life: she was just a high schooler who loved rhythmic gymnastics, being raised by her older brother and sister. However, both of her siblings were hiding secrets about themselves and Sakura that would make her realize that the world around them was not what it seemed. Now, with the help of a mysterious dragon named Yoiyami, Sakura will have to confront these forces and the power within her if she wants to rescue her beloved brother and sister.

Hisui, who works for the Golden Rooster Threatre Group, was orphaned when her parents were killed in a giant massacre ten years ago and her brother Kohaku was abducted. One day, she is summoned to the Emperor's palace and only agrees to go because she suspects that he is behind her brother's disappearance.
Inspired by "The Story of Saiunkoku."
(Source: Day of the River)