During the Spanish Civil War, a command takes the night to reach an advanced position, surrounded by the enemy, to protect the ford of a river. The next day, soldiers from both sides arrange a truce for fishing trouts and exchange cans and cigarettes. But foreign forces relieve the besiegers during the night and kill an unsuspecting soldier who was waving to return to fishing. While the position is strengthened, a soldier escapes to the nearby village to see his family.