I thought the four intertwined stories was neat. It's not just traffic as in drug trafficking, but traffic as in traffic at an intersection where four paths meet and their lives come together, occupying the same general time-space at that moment.
It's actually a lot more complicated than a four-way story, but there are generally four main plots. The events move in two tracks, the crime and the counter crime.
The drugs are coming out of Mexico from one of the two cartels jockeying for business with US distributors like Carlos and Helena Ayala, and eventually out to the streets to the victims like Caroline Wakefield.
Her father, Robert Wakefield, is the appointed Director of the White House Office of National Drug Control Policy. The Drug Enforcement Agency are cracking down on the crime rings and are persuing kingpin distributor Carlos Ayala.
The DEA also have an informant, Javier Rodriguez Rodriguez, who is working for Arturo Salazar who is, in turn connected to the Juarez cartel.
I thought it was tidy and effective to use the blue tint for the victim end of the chain (all the scenes with Caroline Wakefield) and the sepia tint for the source end (all the scenes with Salazar in Mexico). Everything else in the middle is regular coloured — Javier's interactions with the DEA; the DEA with Ruiz and the Ayalas; Helena's interaction with the assassin and the Obregon guy.
Very interesting movie.