Book excerpt: Meet Chris Heifner, overachieving drug runner for a Mexican marijuana cartel. But he wasn’t always. This one-time econ student from Texas—broke, deep in debt, and facing eviction with a growing family to support—yielded to the temptation that he had resisted countless times before and went to work for his best friend from college, Jake Andes. But it wasn’t exactly a Career Day kind of job. Andes was a big-time dealer, captaining a $25-million-a-year empire. Heifner became a mule, running multi-hundred-pound loads from Juárez around the country. After digging himself out of his financial hole, Heifner contemplated going clean. But the money and the lifestyle had hooked him, so he kept moving loads. He was so good that Andes was grooming him to become his second-in-command. And then Heifner got busted with $300,000 worth of dope in a rental car, and his world came crashing down. After bailing out of jail, Heifner went home for a much-needed shower. He emerged to find Andes and a hit man hired to kill him and his family should he decide to narc. Heifner realized that he had only one option: to flip and become an informant for the DEA. That’s when life got really dangerous.