Beginning in 2018, a powerful app for secure communications, called Anom, began to take root among drug dealers and other criminals. It had extraordinary safeguards to keep out prying eyes--the power to quickly wipe data, voice-masking technology, and more. It was better than other apps popular among organized crime syndicates, except for one thing: it was secretly run by law enforcement. Over the next few years, the FBI, along with law enforcement partners in Australia and parts of Europe, got a front row seat to the global criminal underworld.

Over the last decade, a single innovation has massively fueled digital black markets: cryptocurrency. Crime lords inhabiting lawless corners of the internet have operated more freely—whether in drug dealing, money laundering, or human trafficking—than their analog counterparts could have ever dreamed of. By transacting not in dollars or pounds but in currencies with anonymous ledgers, overseen by no government, beholden to no bankers, these black marketeers have sought to rob law enforcement of their chief method of cracking down on illicit finance: following the money.

Meet the Lazarus Group, a shadowy cabal of hackers accused of working on behalf of the North Korean state. It's claimed that they form one of the most dangerous criminal enterprises on the planet, having stolen more than $1bn in an international crime spree. Their targets allegedly include central banks, Hollywood film studios and even the British National Health Service. North Korea denies the allegations, saying the accusations are American attempts to tarnish its image.

Zero day: a software bug that allows a hacker to break into your devices and move around undetected. One of the most coveted tools in a spy's arsenal, a zero day has the power to silently spy on your iPhone, dismantle the safety controls at a chemical plant, alter an election and shut down the electric grid (just ask Ukraine). For decades, under cover of classification levels and non-disclosure agreements, the United States government became the world’s dominant hoarder of zero days.

In 2016, on stage at Wembley Arena, Dr. Ruja Ignatova promised her followers a financial revolution. The future, she said, belonged to cryptocurrencies such as Bitcoin. And the Oxford-educated, self-styled cryptoqueen vowed that she had invented the Bitcoin Killer. OneCoin would not only earn its investors untold fortunes; it would change the world. By March 2017, more than $4 billion had been invested in OneCoin in countries all around the world. But by October 2017, Ruja Ignatova had disappeared, and it slowly became clear that her revolutionary cryptocurrency was not all it seemed.