Over the past several years, daily fantasy sports have become big business, with gamers and fans betting an estimated $2.6 billion in 2015. Critics say the practice amounts to gambling and should be regulated, but companies like DraftKings and FanDuel say it’s entertainment.

With several U.S. states questioning the legality of daily fantasy sports, FRONTLINE and The New York Times investigate the reality behind their rise and the proliferation of online sports betting despite the laws meant to stop it. Walt Bogdanich, James Glanz and Augie Armendariz of The New York Times trace the growth of these booming businesses, go inside their operations at home and abroad and reveal how online gambling laws have not only failed to stop the illegal sports betting business, but enabled the growth of the daily fantasy sports business. Through interviews with prosecutors, regulators, gamblers and a high-tech investigation into the inner workings of e-sports gambling at home and offshore, The Fantasy Sports Gamble is an inside look at both the technological war between the government and the gamblers, and how daily fantasy sports sites factor in to it all.