During the Anti-Japanese War, in Baiyangdian, Hebei, the naughty and reckless teenager Zhang Ga (Angis) witnessed his grandmother being killed by the Japanese invaders for covering the escape of the Eighth Route Army. He came to the county alone to find the guerrilla platoon leader Luo Jinbao (Zhang Ying) so that he could help avenge his grandmother. However, when he really met Luo Jinbao, he regarded him as a traitor and made a joke. After the misunderstanding was resolved, Zhang Ga dreamed of becoming a little Eighth Route Army soldier and wanted to own a gun. As a result, because he wanted to get a gun too much, he not only cheated when betting with Pang Dun (Wu Keqin), but also violated discipline and secretly hid the real gun confiscated in a battle in a bird's nest on the tree, making another joke. Zhang Ga didn't take the joke as a joke. He couldn't figure it out, so he made an appointment with Pang Dun to come to the county again to avenge his grandmother. In the county, Zhang Ga met the devil Guitian (Ge Cunzhuang) and the fat translator (Wang Shu). After a battle of wits and courage, the two did not get any benefits from Zhang Ga. After a series of events, Zhang Ga grew from a reckless boy to a true little scout of the Eighth Route Army.