The propulsive, untold story of an unlikely group of fraud victims who joined together to expose a sinister, multi-billion-dollar criminal operation preying on the American public—a crypto true-crime saga in the tradition of Black Edge and Bad Blood.

The cryptocurrency brokerage looked so real. Its phone app even allowed customers to withdraw profits after an initial trade or two. But when the company notified Brian Bruce that his funds were frozen until he deposited another $61,000 to “verify” his account, Bruce knew that he’d been scammed. The former colleague who’d contacted him on LinkedIn, the thousands of dollars he’d made trading crypto—it was all an illusion.

For most Americans, the story ends there. But for Bruce, it was only the beginning. On his laptop, he traced the flow of his stolen money through the cryptosphere. As he did, Bruce linked up with more and more victims of what’s cruelly known as “pig-butchering”—a growing class of investment fraud, which has now outpaced business-email compromise as the costliest form of cybercrime. Before long, these citizen-investigators had formed a vigilante group: the Global Anti-Scam Organization. And the deeper they probed, the more hellish their discoveries became. The clues led them to Laos, Cambodia and the lawless Thai-Myanmar border, where Chinese criminal syndicates had constructed massive, fortified compounds—one the size of a small country—to house scammers. But the people on the other end of the texts and social media messages were often victims, too: in this case, of the shocking modern practice of cyberslavery. To truly achieve justice, the investigators would not only need to expose the criminals; they would also have to rescue the people who’d been forced to defraud them.

A gripping nonfiction thriller, The Big Trace unveils this dark nexus of online scams, cryptocurrency, and modern slavery. Drawing on four years of extensive, exclusive reporting, award-winning investigative journalist Cezary Podkul shines a light onto a menace lurking behind all of our smartphones—and shows how tackling this global threat is not only possible but essential, for our sake and for the good of humanity.