A man called "The Black" is hired to smuggle a group of undocumented migrants into the United States. He wants to quit the smuggling business and claims this is his last trip. His superiors, now suspicious, send Gavilan, a younger smuggler, to keep an eye on him. During the troubled crossing, the smugglers fight and eventually lose part of their human cargo. "The Black" escapes from his former associates but also needs to ecape from the Border Patrol.

Tells the parallel stories of nine-year-old Carlitos and his mother, Rosario. In the hopes of providing a better life for her son, Rosario works illegally in the U.S. while her mother cares for Carlitos back in Mexico.