El porqué del color rojo

The harvest begins in La Rioja Baja. Tractors invade the highways and seasonal crews, arriving from all over, work hard to harvest the grapes. At dawn, an anonymous call notifies the Calahorra Civil Guard barracks: the body of a young man has been found abandoned in a vineyard near Aldeanueva de Ebro. Everything suggests that he is an illegal seasonal worker from Eastern Europe, forced to work for a mafia. Lieutenant Lucía Utrera, alias la Grande, begins by investigating the case as a shallow affair with the only help of a team of inexperienced guards and a priest with problems controlling her anger.