Episode 1 Introduction: The "good kid" Qiao Nianchao and the self-proclaimed "commander" Zhang Weiping, who live in the same compound, secretly sneaked into the sealed military district library - Qiao Nianchao was stealing books to give his sister Qiao Jianxin a birthday gift; while Zhang Weiping was after a historical artifact - a box gun. Unexpectedly, they startled Private Xiao Zhao from the guard company. In the ensuing confusion, while fleeing, Zhang Weiping and Qiao Nianchao mistakenly grabbed each other's schoolbags, even knocking Xiao Zhao unconscious in the process. The box gun was lost, and as a result, a special investigation team was set up in the military compound to look into the matter. Fang Wei is Qiao Nianchao's classmate since kindergarten, elementary school, and high school. With Fang Wei's help, Qiao Nianchao returned home, only to find that he had mistakenly taken Zhang Weiping's bag, which surprisingly contained a box gun! The next day, he returned the bag with the box gun to Zhang Weiping.