The rookie agent Song Yunong admires her aloof yet passionate senior brother Xie Zuiqiao. However, due to her recklessness and inexperience, she frequently gets reprimanded by Zuiqiao and is taken on missions without ever being given the chance to fire a gun. The marksman Xie Zuiqiao, known for his exceptional skills and ruthless character, is referred to as the "Fiery Marksman" due to his accurate shooting. During an important mission, a dangerous fugitive known as Black Second Hand causes chaos at the headquarters. The officer who promoted Song Yunong, Lou Qun, faces blame and, in a fit of rage, criticizes Yunong for her inaction. Out of anger, Yunong chases after Black Second Hand, always trailing behind Zuiqiao and wanting to take down the enemy but ends up failing. Zuiqiao sacrifices himself to protect Yunong and is killed. Yunong is rescued by her teammates without even being able to retrieve Zuiqiao's body. When she awakens again, she discovers that this title has somehow been bestowed upon her; no one remembers Xie Zuiqiao, nor have they seen his corpse. Yunong tries to uncover what happened to save her senior brother, reaching out to those connected to him, including Officer Lou Qun and Sha Ming, the owner of the shop that sells Zuiqiao’s rifle. Through their contradictory narratives, she realizes that Zuiqiao's death was the result of his own choices... multiple cycles each pointing to...