It was always a crime story hiding in plain sight. From 1987 to the 1990s, McDonald’s crowned dozens of winners in its promotional Monopoly game, which awarded customers prizes ranging from a free drink to a car to a million dollars. Big-time winners – the rare ticket-finders – were interviewed on the news and profiled in the papers. Except none of the winners were real. Or rather, none actually stumbled upon a lucky ticket. They were picked in a scheme run by a rogue ex-police officer, Jerome Jacobson, involving mob connections, false addresses, smuggled tickets and over $24m in illegal winnings – a genuinely crazy, rabbit-hole story of greed, deceit, and good old American scamming explored in McMillions, a six-part HBO docuseries out this week.

The series kicks off in 2001, when Doug Mathews, a young and hungry FBI officer who seems more at home at a southern barbecue than a law enforcement office, stumbles upon another bombshell in plain sight: a Post-it note on his boss’s desk that simply asks: “McDonald’s Monopoly Fraud?” Mathews and his team in Jacksonville, Florida, have one lead – an anonymous tip that some past winners know each other – and little reason to doubt the security of one America’s largest food chains. Without spoiling too much, things quickly expand from Jacksonville to winners up and down the east coast, a nightclub owner resembling Al Capone and a network of stolen golden tickets.

Though the story seems tailor-made for an Adam McKay movie or bestselling book, it remained largely hidden for years, in part because news of the investigation dropped right before 9/11. The McMillions co-director James Lee Hernandez didn’t hear of it until 2012, when he scrolled through Reddit to kill time before bed and saw a post in the TIL (Today I Learned) thread: “Today I learned nobody really won the McDonald’s Monopoly game.” As someone “obsessed” with the game as a child – his first job was working for his local McDonald’s – Hernandez started digging. There wasn’t much – an article in a Jacksonville newspaper about the mail fraud indictments of false “winners”, but nothing with a bird’s eye picture of the story or FBI investigation. The missing information “set me on fire”, he told the Guardian. “In this day and age, if you can’t learn every single thing in two seconds on the internet, it drives you crazy. So I kept looking into it.”

Hernandez put in Freedom of Information Act requests with the federal government, which took three years to materialize and revealed names of those involved in the investigation. In 2017, he reached out to FBI agents and prosecutors, who all “said this was their favorite case they’ve ever worked but nobody’s ever reached out to them”, he said. Hernandez teamed up with a fellow film-maker, Brian Lazarte, to start interviews, eventually linking up with Mark Wahlberg’s production company Unrealistic Ideas and HBO.

Though the facts of the case are by now well documented, the six-part series unfolds through the eyes of FBI investigators as they attempt to assemble a series of loosely connected clues – an anonymous donation of a $1m Monopoly piece to St Jude’s Children’s Research Hospital in Tennessee, a tapped phone call referring to a mysterious “Uncle Jerry” – into a coherent picture. “We were just fascinated by their investigation,” said Hernandez. “How do you take this extremely small kernel of information and blow it out to this massive case? We wanted to make sure we were never ahead of the FBI investigation, so you could live it as they lived it.” The viewer, then, learns new information on the mechanics of the scheme and the colorful characters involved (besides Mathews, there’s a campily dressed mob ex-wife, among others) in the same chronological order as the FBI. The three episodes available for review lead you deep into a morass of shady connections, strip clubs, stolen Monopoly pieces and side-of-the-road dealings with no clear explanation for how, exactly, Jacobson and his conspirators pulled it all off.

FBI Special Agent Doug Mathews in McMillions. Photograph: HBO

The focus, instead, is the daring tactic to keep the investigation under wraps: a fake production company fronted by Mathews to stage a fake “winner’s reunion”, with help from McDonald’s executives. The ruse allowed the FBI to check in, with cameras and questions, on past false winners and provides plenty of archival footage, which Hernandez and Lazarte pepper in amid hazy re-enactments and interviews.

The harebrained and at times surprisingly haphazard scheme, along with Mathews’s charisma, casts a lighthearted, caper-oriented tone on the series. But Lazarte and Hernandez balance the zaniness with a serious reconsideration of the scam’s impact on the winners, some of whom were convicted on federal charges. “A lot of people say, well, it was a victimless crime – they weren’t hurting anyone, it was a billion-dollar corporation, they’re not suffering as a result of this,” said Lazarte. Both are vague on the revelations of the final three episodes, but the truth, they found, was more complicated. One false winner, Gloria Brown, seems coldly dishonest in archival footage from the “winner’s reunion” interview; in McMillions, she explains her context: the struggle of being a single mother, her belief the ticket was a gift from God to get her son a step ahead. “Everyone who was alive at that time wanted to win that game,” said Lazarte. “If a family member came to you with the opportunity to claim a prize and all you had to do was say you’re the one who peeled that game piece, would you have done it?”

The series tracks a web of lies with soap opera-level twists and, naturally, the relish of a good scam story. But ultimately, “there are victims, and there are some serious consequences for what might seem like a small white lie,” said Lazarte. “We’ve always felt there’s a great takeaway in that, and I think that people will see by the end of the series.”