It dramatizes the social changes experienced by the city in a major "before" and "after" the World Expo, honing in on the process of cleaning up the city, eliminating the drug dealing from the streets in preparation for the World Expo, from the point of view of four (and particularly two) police officers comprising the (fictitious) Unit 7, renowned for their exaggeratedly elevated drug bust rate.

The film discusses the concept of the end justifying the means, focusing on themes of corruption, police violence, the psychology behind the figures carrying it out, and the politics (embodied by the police chief and unseen politicians) giving them carte blanche to do so, while washing their hands of the dirty deeds, condemning their actions when scandals break and condoning them when major drug busts are successful.

[1] Unit 7 has a tough assignment: to clean the most dangerous drug trafficking networks out of the city and bring an end to the corrosive power that has taken hold of the streets.

A detail of four, the unit is led by Ángel, a young officer aspiring to the rank of detective, and Rafael, a violent, arrogant, yet efficient cop.

Angel takes the path of ambition and police excess while Rafael will begin to change as a result of his feelings for beautiful, enigmatic Lucia.