In the city of Wuxi, the night was dark and the wind was strong. Guerrilla fighter Lin Xiao Jie and her fiancé Ah Tian were escorting two boxes of penicillin they had just seized from the Japanese devils back to their organization. However, on the way, they encountered the traitorous soldier Liu Er, and after a fierce battle, Ah Tian was captured while trying to protect Xiao Jie, and the two boxes of penicillin fell back into the hands of the traitors.Lin Xiao Jie escaped in pain, but she could never forget Ah Tian, and she could not forget his last words when he was captured; she must find those two boxes of penicillin.Not long after, Lin Xiao Jie returned to Wuxi as a student and connected with her brother-in-law and underground guerrilla fighter Mu Rong Xuan. However, she was unaware that her twin sister Lin Xiao Ting had already infiltrated the Japanese military's special intelligence section, becoming an able aide to Section Chief Gao Jia Ju, whose task was to find those two boxes of penicillin.At this time, the Japanese military had already sensed the guerrillas' movements, and there were no leads on the two boxes of penicillin, causing much anxiety for both Xiao Ting and Xiao Jie. Especially since Xiao Jie, in a moment of impulsiveness, assassinated the traitor Liu Er who had been capturing Ah Tian, prompting Section Chief Gao Jia Ju to intensify his hunt for the underground guerrilla fighters. Soon, he found a lead, a university student with the nickname 'Little Guandong'.At this moment, Lin Xiao Jie observed that the Japanese army was stationed at a certain location...