Su Qi Xu wakes up in a secret order that belongs to highly skilled assassins. She must now enter the order as a novice and train to survive. She meets Chang An who is a slave there. His late master is dead and if he cannot find a new master he will be killed. Su Qi Xu picks him as hr shadow in order to save his life. In return, Chang An helps her maneuver the new environment. (Source: Autumn carrot at MyDramaList)