She is called An Jiu, but she is the scythe in the hand of death, the killer who sinks into the eternal night, struggling hard for that out-of-reach ray of light. She was injured in a mission and met Mei Jiu. Together with the kind and weak girl, Mei Jiu, they enter the Mei Mansion. An Jiu then realized that there were suspicious things one after another, leaving her with no choice but to hide her real strength. Not long after, she discovered the Mei family's secret: they train secret bodyguards for the royal family and are actually one of the most ancient families of secret killers of the Song Dynasty.

She gradually became good friends with Mei Jiu and also secretly fell in love with the master who taught her martial arts, Chu Dingjiang, the commander of the Crane Control Army.

It tells the story of a widow, Jun Qinglan, who disguises herself as a man and joins the Imperial Guard to clear her family's sorrows. After going through hardships, she finally lives with her beloved. A story of blood and tears of fighting for a happy life, without shame or embarrassment.