It's Christmas in Culiacan and Detective Edgar "Lefty" Mendieta can't believe his luck. An old flame has returned with a teenage son he knew nothing about. Happiness seems to finally beckon for our careworn hero. The only snag is that Jason Mendieta wants to follow in his father's footsteps-even as Mexico's drug war descends a slippery slope toward chaos.While Lefty pursues a lunatic who has taken to bumping off dentists with a heavy-calibre pistol, a secret agent infiltrates a meeting of the drug lords and hears Pacific Cartel boss Samantha Valdes implore her underlings to stay out of the war. But an audacious murder provokes Samantha to change her mind and launch a wave of grisly killings across the country.Samantha then persuades Lefty to help her find the killer that pushed her over the edge. The truth he discovers will underline an old adage: revenge is a dish best served cold. No quiet family Christmas for our detective.