Bilbao. The commander of the Guardia Civil, Evaristo Torrecuadrada discovers that his son Paco of 17 years old is a heroin addict. His hope was to see him in the Military Academy. Paco, by differences with his father, runs away from home with a pistol. The commander begins his quest aided by co-Body, using the means at its disposal to achieve its objective. Lt. Alcantara, an expert on drugs, will be one of the most prominent in this quest. The Civil Guard Commander begins to discover a world that knew nothing. Urko's father, nationalist leader with a heroin adict son, helps in some way to find out. His principles, his life, his struggle, fall into a deep crisis, exacerbated by the developments ....