The Golden hairpin

the long version

"In ancient China, history, vengeance, and murder collide At thirteen, investigative prodigy Huang Zixia had already proved herself by aiding her father in solving crimes. At seventeen, shes on the run, accused of murdering her family to escape an arranged marriage. She must use her skills to unmask the real killer and clear her name. But when Huang Zixia seeks the help of Li Shubai, the Prince of Kui, her life and freedom are bargained: agree to go undercover as his eunuch to stop a serial killer and to undo a curse that threatens to destroy the Princes life."--Page 4 of cover