Set in the latter period of the Spanish Civil War, the film features an ensemble cast of Miki Esparbé, Aura Garrido, Luis Callejo, Álvaro Cervantes, Jesús Carroza and María Botto.

During the Spanish Civil War, a column of Waffen-SS troops arrive at a village and slaughter the inhabitants before hurling gas canisters containing a substance onto the corpses.

Arriving at their recently bombed encampment, they are attacked by their reanimated comrades, forcing them to escape by boat, but Brodsky, the Russian member of the group, is overwhelmed by the infected.

Reaching a cabin, they find it occupied by Nationalist soldiers Jurell and Rafir, and a nun, Flor, resulting in a standoff that lasts until Jan convinces the two sides to form a truce.

Jurrel and Rafir later spot a large horde of infected heading towards the cabin, and Sergeant orders an evacuation who they all manage to escape.

At the village, they find a lone survivor of the earlier massacre—Ana, who was shielded by her husband from gunfire and says that the SS conducted experiments until they were slaughtered by the infected.

Jaime, the Republican unit's commissar, discovers the formula for making zombies and plans to bring this to his superiors to win the war.

Jan and Priest-killer, the only woman in the Republican group, storms the laboratory train car and confronts the SS commander, who injects himself with the formula and declares there is no antidote.

German bomber planes arrive and pummel the valley, obliterating the base and engulfing the train as Jan and Priest-killer kiss.