One anonymous football fan.

18.6 million confidential documents.

This is the explosive story of the biggest leak in sporting history - and the shady underworld of modern football.

In 2016, a whistle-blower known only as 'John' started to leak a treasure trove of top-secret files to German newspaper Der Spiegel. These documents reveal the clandestine dealings of clubs, players and agents at the highest echelons of international football. And the story they tell is astonishing.

From the eye-popping details of player transfers, including Neymar Jr, Pogba and Coutinho, to the loopholes and opaque tax structures that ensure maximum earnings for players and agents alike, this is a tale rife with rapacious greed and questionable deals. At the same time, it is the gripping story of a fan who wanted to free football from its corrupt overlords - and now finds himself on the run.