Forget you have children. This advice was given to Mario, an illegal immigrant, by his new boss from Xalisco, Nayarit. Mario was preparing for what turned out to be a short career as a dispatcher for a black tar heroin cell in Columbus, Ohio, a few years after the Man brought the drug there. “Forget that people may do to your kids what you’re doing to the children of others,” his new boss told him in a restaurant one day. “Otherwise you won’t sleep.