Based on a true story in Sichuan’s Xingwen County, Lone Army follows the Red Army guerrilla fighters on the Sichuan-Yunnan-Guizhou border. Against overwhelming odds, they launch desperate battles with an unyielding will to fight to the last man. With nearly the entire unit sacrificing themselves, they complete their glorious mission—covering the strategic retreat of the Central Red Army and the Second and Sixth Corps.
- This film is adapted from the true historical story of Xingwen County, Yibin City, Sichuan Province and the Sichuan-Yunnan-Guizhou Border Region. It tells the deeds of the Chinese Workers' and Peasants' Red Army's Southern Sichuan Guerrilla Column (also known as the Sichuan-Yunnan-Guizhou Border Region Guerrilla Column).
- During the Long March, this guerrilla column was responsible for supporting the strategic transfer of the Central Red Army and the Second and Sixth Red Army Corps, reducing the enemy's pressure on the main force of the Central Red Army.
- The film's creators have emphasized on many occasions that "the character creation and story background are all based on real historical events."