You could buy any drug imaginable, wherever you were in the world, on the Silk Road website.

Hidden on the dark web, it made millions of dollars every week. The US government had been trying to shut it down for more than two years when tax agent Gary Alford was brought in to try to trace the money which passed through the site.

In his spare time, Gary started searching Google to try to find the mysterious mastermind behind the site: Dread Pirate Roberts.