After the fall of Peking, Su Wanqing, a female student at Yanjing University, fled to Taihang with an encrypted map left by her father and accidentally joined the underground transportation line. She gradually grew up from an intellectual holding a pen to a "Qingping" who could convey information in a hail of bullets. She used wisdom and courage to deal with the Japanese army, puppet troops and bandits. In the wind and snow of the Taihang Mountains, she protected the lives of her comrades and the hope of the war. She also found her true "sword" - not the antique sword left by her father, but the belief in protecting her family and the country.
