In a bid to take down MS-13's criminal network in the Mission District of San Francisco, Michael Santini, a special agent with Homeland Security Investigations, recruits a pair of hardened gang members and convinces them to risk their lives as criminal informants. Set in a city with one of the strictest sanctuary policies protecting illegal immigrants in America, Operation Devil Horns illustrates how politically correct ideology impacts life-or-death crime fighting on the streets.

Through the informants' eyes, Operation Devil Horns offers a rare glimpse into the pervasive criminal subculture of MS-13, a gang of Spanish-speaking immigrants that still terrorizes pockets of American society today amp;mdash; including their own compatriots.

The case begins with a focus on the gang in San Francisco, eventually widening to include a network that reaches across borders. Santini tracks down the gang's leadership from the Bay Area to the prison cells of corrupt Central American regimes. Eventually, it takes the cold-blooded murder of three family members in San Francisco to shake the American public out of complacency and focus sober attention on a growing and violent threat.