Assembly

During the 1948 Huaihai Campaign, Captain Gu Zidi leads the 9th Company of the 139th Regiment to seize a town controlled by the NRA. They suffer heavy casualties from intense enemy fire. Gu, enraged by the death of his political commissar, orders the execution of surrendered NRA soldiers, an act that earns him three days in jail.

Gu is jailed for three days by Colonel Liu Zeshui after the incident with the surrendered NRA soldiers. While in jail, he befriends Wang Jincun, a foot soldier and former teacher who has been jailed for cowardice.

Upon release, Gu and his surviving men are assigned to defend a coal mine on the Wen River near Tai'an, Shandong, holding their position until a bugle call for assembly. With Liu’s permission, Wang Jincun becomes the 9th Company’s new political commissar, bringing education and leadership to the unit.

The 9th Company comes under heavy attack by NRA forces, repelling infantry and armor and destroying two tanks. By the end, only a handful of men remain. Gu, who has been temporarily deafened by an explosion, refuses to believe the bugle call is real and orders the survivors to fight to the death; the unit is wiped out except for Gu, who is knocked unconscious by a tank shell.

PLA forces recapture the area and find Gu unconscious wearing an NRA uniform he had stolen to survive behind enemy lines. At a military hospital, Gu attempts to prove he is a PLA captain, but a reorganization has erased memories of the 139th Regiment, and other patients treat him as a deserter.

In 1950, China enters the Korean War and Gu volunteers to fight as a PVA infantryman. On an artillery-spotting mission, Gu and his team disguise themselves as soldiers of the Republic of Korea Army's 6th Infantry Division to protect their unit commander, Lieutenant Zhao Erdou, after Zhao steps on a landmine. Gu holds the landmine down during the blast and escapes, but loses his right eye in the explosion; the two become close friends and Zhao supports Gu's bid to regain recognition for the 9th Company.

After the war, Gu returns to the Wen River battlefield and tries to locate the old mine. He discovers the mine is still operating and the entrance is buried beneath piles of coal. He also meets Wang Jincun's widow and convinces her to marry Zhao Erdou.

Zhao Erdou finds the tomb of Colonel Liu Zeshui, whose caretaker reveals that the bugle call was never sounded and the 9th Company was sacrificed to buy time for the rest of the regiment. Gu initially erupts in anger but calms himself, accepting the painful truth.

Gu camps at the mine and begins digging out the bodies with a shovel, despite resistance from the miners. A surviving former officer of the 139th Regiment comes forward a month later to verify the unit’s deeds, and the PLA issues an official notice to honor the 9th Company.

A memory reveals that as enemy forces closed in, Gu and Wang buried the other bodies deep inside the mine. When Gu left to fight, a mortally wounded Wang blew up the entrance to prevent capture, sacrificing himself for his comrades.

Years later, the remains of the other soldiers are found during an irrigation-project excavation, and the PLA erects a monument near the site to honor the 9th Company. Gu is unable to locate the final bodies but accepts the broader tribute.

The PLA conducts a military funeral with full honors for the fallen 9th Company and erects a monument at the site. Gu finally finds some peace as he comes to terms with the sacrifices of his comrades.

Ending titles reveal Gu died in 1987 at the age of 71. They also recount his origins — abandoned as an infant during famine, found by a shoemaker in a millet field and given the name Gu Zidi, which literally means millet field.