With its sandy beaches, Spanish colonial architecture and volcanic lakes lined with restaurants, El Salvador has all the assets of a dream tourist destination. Yet foreign visitors are rare. The reason: this tiny state in Central America is the most dangerous countries in the world. Every year, between 3,000 and 6,000 people are murdered, in a population of only 6 million. Since the 1990s, the country has been torn apart by a violent gang war. Members of MS-13 and Barrio 18 fight a bloody war for control of the neighbourhoods. 

Julio, one of the leaders of Barrio 18, opens up before the camera and lets us film the violent induction ceremony for a new member. We also meet Zorro, a hitman who committed some of the worst atrocities. Forensic pathologist, Riccardo, specializes in the toughest crime scenes. This morning, he is investigating three dismembered and decapitated bodies that have just been found in a ravine. His colleague Israel Ticas, a forensic criminologist, is working on a politically sensitive mass grave where 26 bodies were buried some 15 years ago. 

Among the victims, there are police and soldiers executed by gangs. For this documentary, the Salvadoran government also authorized us to enter the high security prison of San Francisco Gotera. Inside, 1,700 gang members are held in deplorable conditions of hygiene and overcrowding. 

From morning to night, the prisoners are subjected to a true evangelical religious conditioning and the sworn enemies of rival gangs must learn to cohabit in the same cells. Welcome to the world of the Salvadoran mareros, a ruthless universe where death punctuates daily life and where people murder for a fistful of dollars.