The film focuses on the Iron Triangle Blocking Battle. In May 1951, the 63rd Army of the Chinese People's Volunteer Army had just ended a month of combat and was ordered to enter the Iron Triangle battlefield to confront the four divisions of the "United Nations Army". The volunteers fought bloody battles and finally brought the enemy to the negotiation table. In order to complete the task, the soldiers of the 189th Division of the 63rd Army were divided into pieces, turning themselves into a nail and firmly nailing them to the position. On the position of the 1st Battalion, Li Xiang (played by Zhu Yilong), the battalion instructor, made a vow of "never retreating a step" and defended the position to the death. In the midst of the artillery fire, Li Moyin (played by Xin Baiqing) and his family of three reunited on the battlefield. A key and a reunion dinner in the trenches made this small family separated by the war more intimate. In order to make better weapons for New China, Wu Benzheng (played by Zhu Yawen), a returning military expert, entered the battlefield under the protection of Zhang Xiaoheng (played by Ou Hao). As a guard, Zhang Xiaoheng firmly believed that guarding Wu Benzheng was guarding the future of the motherland. Sun Xing (played by Chen Feiyu) and Yang Sandi (played by Zhang Youhao) also came to Cheorwon. All the soldiers of the 63rd Army built an unbreakable "Iron Great Wall" on the battlefield of Cheorwon!