When an American judge known for anti-immigration views is found dead on the bridge connecting El Paso, Texas, with Juarez, Mexico, authorities from both sides of the U.S.-Mexico border must work together to catch the perp, a serial killer who is operating in both countries. Detective Sonya Cross, of the El Paso Police Department, works with Chihuahua State Police Detective Marco Ruiz, who knows about the slippery politics of Mexican law enforcement. Ruiz's whatever-it-takes approach doesn't sit well with Cross, who has Asperger's syndrome and a by-the-book attitude when it comes to the job. But the two put their differences aside to solve a string of murders on the border, which is already infected with issues that include illegal immigration, drug trafficking, violence and prostitution.