Now I understand why the US lost the Vietnam War. The official historical account, with its heroic overtones, takes a back seat. This is not a portrait of characters, but of men and women in a dark tunnel. The guerrilla fighters who defended an almost suicidal cause in the US Operation Cedars attack in 1967 are seen as flesh and blood. The leader Bay Theo despairs and curses because the young women do not obey him and leave the shelter; the prisoner Tu Dap lies about an imaginary mother and family he shares with Lieutenant Miss Ba in order not to be shot, and to build mine devices; Miss Ba is jealous of the devices that Tu Dap gives to the others before her.

It will immediately become obvious that the guerrillas, most of them young, were not ready to serve in the Binh An Dong (Cu Chi) underground tunnel, which covers around 400 square kilometres, because their experience was in setting traps and bombs rather than in combat in bunkers and against M48 Patton tanks or M41 Walker Bulldog tanks. The film not only recreated a 250-metre tunnel in Cu Chi, but also received government support to represent and use war machinery found in museums, such as the one in Hanoi, and Vietnamese plans to give it unparalleled realism, in accordance with those used at the time.

Furthermore, as can be seen from the plot in the tunnels, the use of Viet Cong punji traps was not neglected either. These were made of bamboo and metal stakes similar to those used at the time, smeared with excrement to cause infections in the bleeding American enemy. And we cannot forget we will see the holes that Miss Bay uncovered as she fled, holes with the green viper known as the green bamboo viper (Trimeresurus albolabris) with haemotoxic and neurotoxic venoms that cause necrosis and/or immediately paralyse the respiratory and cardiac systems.

While Hai Thung coordinated the hurried telecommunications logistics with Bay Theo and his squad, Uncle Sau harangued everyone with speeches, after meeting briefly in another section of the holes to watch films on reel-to-reel tape, films in which they themselves were the protagonists because they were selfies or videos of their work in camps or training. Unfortunately, they are discovered, and Uncle Sau asks Tu Dap to blow up the entire section where he is located.

Tu Dap surrenders to entertain the Americans and buy time for his comrades, but also to gather many enemy soldiers, along with the interpreter, and blow them up in a suicide attack. At 00:58:06, Ut Kho and Bau Huong are trapped in a section of the tunnel that is flooded, and Bau Huong says she will stay with Van because she is pregnant. However, Miss Ba saves her and reveals her pregnancy to Bay Theo so that he can find the person responsible, or the father.

Meanwhile, Miss Ba cannot resist falling in love with Tu Dap, who continues to set traps and explosive bombs, one of which we see blow up an American combat boat, killing the enemies in a fire. The objective will be achieved, defending the strategic telecommunications system or office, but at such a cost that even Bay Theo dies longing for a cup of tea and the enthusiastic Viet Cong are decimated, although the losers will be the American invaders sooner or later, as history reminds us.