Young people from different backgrounds are studying martial arts at the Assassin Academy. Han Xiao Chu, the top school student, was the first to go out on outside mission. She was accompanied by the student Long Bi Xie, the last placed student. During the mission, something happens and Xiao Chu awakens back at the academy with all students missing the memory of Long Bi Xie and him also missing. (Source: Michaela H at MyDramaList)