Underworld Inc. follows the dirty drug dollars from American trap houses to wholesalers and transporters, funnelling billions into Mexico’s money laundry. US authorities are closing in on cartel cash. If drug lords want their narco cheddar cleaned and moved into the banking system, they have to get it to Mexico. Working to stem the tide, the cops hit stash houses, and interdiction teams tail cars suspected of smuggling millions. South of the border, launderers use money changers to turn drug profits to pesos for onward investment in front companies and bogus construction projects. If local authorities pry into these shady businesses, they get warned off – cartel style.