Synopsis：In 1937, Tong Jiaru (played by Yang Zhigang), a native of Rehe, leaves his hometown to teach Mandarin at Nie Zhongcheng Middle School in Shanghai. However, his adopted daughter, Nannan, becomes disabled, forcing him to stay when he intends to flee south again. Witnessing the invaders tormenting his compatriots, he swallows his anger and focuses solely on saving his own life. Student Ouyang (played by Zhang Jiayi) is serving the country and urgently needs assistance, compelling Tong Jiaru to help. Ouyang sacrifices himself, and Tong Jiaru becomes a target of the Japanese spy Dongcun. He skillfully completes tasks and dispels suspicion. Ouyang's boss, Yang Xiao, is captured, and Tong Jiaru rescues him. His wife, Zhi Zi, has just given birth to their son, Hope, but is killed while protecting Yang Xiao. Within half a year, the four assassins involved in Zhi Zi's murder are all killed by Tong Jiaru without a trace. Frustrated by a lack of evidence, Dongcun attempts to force Tong to confess using brutal torture instruments. The Communists organize teachers and students to rescue Tong Jiaru. Three years later, Tong Jiaru uses himself as bait to help comrades from both parties unite to eliminate the Japanese spy base. The Japanese invaders surrender, but Dongcun refuses to accept defeat and kidnaps Hope, forcing Tong Jiaru to fight him. Comrades subdue Dongcun and rescue Hope. Dongcun curses Tong as a coward, and Tong Jiaru tells him: "The Chinese have a courageous heart when facing invaders."