This film tells the story of Zhang Si De, a model of the Chinese People's Liberation Army. In the late period of the War of Resistance Against Japan, Yan'an was in a mass production movement. The service soldier Zhang Si De (Wu Jun) is honest, unspoken, never invites merits for doing good things, works hard and never complains, and devotes himself to the Chinese revolutionary cause.

Prompted by the death of his father and the grief of his mother, a man recalls the story of how they met in flashback.

During the Sino-Japanese War, Commander-in-Chief Zhu De leads the Eighth Route Army in pivotal battles against the Japanese invaders.

The Japanese has invaded far into china, defeating the Kuomintang (KMT) soldiers many times and pushing them back into Central China. There was a general sentiment among anti-Japanese resistance forces that the Communist Party of China (CCP) was not contributing enough to the war, and that they were only interested in expanding their power. As a result, the CCP planned a major offensive against the Japanese, consisting of 105 regiments, called the Hundred Regiments Offensive.

Dongdong's father financially supports the family with low wages alone. However, he quitted his job in order to retain his colleague's job, because he sympathy her, who is a single mother. This made their living became worse, and drove his mother left with her past lovers. To earn living, Dongdong has to work with his father and lost the chance of schooling. Missing mother drives them nuts, and they decided to go to Dalin to find her. The journey of searching mother begins.

After work, the boss asks Chen Xiao to work overtime. Hesitant, she feels watched and pursued by a giant high-tech eye. After agreeing, she must face endless overtime hours.