A year after Colorado passed one of the most permissive pot laws in the world, CNBC and correspondent Harry Smith return to the state to chart the rise of a new American industry and report on the results of this unprecedented social experiment. Smith profiles the most successful marijuana merchant in Denver, who hopes to expand his family-run business to other states as they follow Colorado's lead and legalize the sale of marijuana for recreational use. He explores the new world of cannabis-infused edibles and the sale of pot brownies, chocolates and even soda, which has led to some confusion and controversy over dosing and portion size. CNBC cameras also follow two pot dealers – one of them a U.S. Army veteran – who profit from a black market that funnels the drug across state lines and continues to thrive despite the new law.