A dead body is found on the bridge connecting the USA and Mexico, forcing Sonya Cross (Diane Kruger) from El Paso PD and Mexican policeman Marco Ruiz (Demián Bichir) to work together to catch a grisly serial killer. Marco will do whatever it takes to get what he needs, but Sonya strictly follows rules and protocol. The case leads them to a string of murders on both sides of the border.