Who wouldn’t want to win a million dollars on “Who Wants to be a Millionaire”? But what would you do to take home the top prize? Would you cheat?

What if you did cheat, and you got caught?

What if you didn’t cheat, but everybody thought you did?

There are more questions than answers in the three-part AMC drama “Quiz,” which recounts the real-life scandal that erupted when Charles Ingram (Matthew Macfadyen) won a million pounds on the original, British version of the game show — only to have the check canceled and charges brought when producers and the police became convinced he cheated.

Did he? Well, the three-hour AMC/ITV co-production makes a strong case that he did. And then it makes an even stronger case that he didn’t. Which makes for an unsettling and somewhat unsatisfying conclusion to “Quiz,” which begins airing Sunday at 11 p.m. on AMC.

(Episodes 2 and 3 air the following two Sundays at 10 p.m.)

What the show does incredibly well is tell the story of how “Millionaire” became a megahit in the U.K. and around the world, including in the United States. Despite the skepticism of ITV programmers, a third of the U.K. population tuned in. In the U.S., upward of 30 million people flocked to their televisions to watch Regis Philbin ask contestants if that was their final answer.

Two decades later, “We kind of forget” how big the show was, said Sian Clifford, who stars as Diana Ingram, the major’s wife and alleged co-conspirator. “At the time that was the biggest prize money ever being given away on a game show, so it was huge. It was historic.”

(Yes, the Ingrams really are named Charles and Diana.)

(Photo courtesy of Mark Johnson/AMC) Sian Clifford as Diana and Matthew Macfadyen as Charles in "Quiz."

“It was like it was more than a TV show,” said Michael Sheen, who stars as the original host of the British version of the show, Chris Tarrant. “It was a sort of phenomenon — a cultural phenomenon. And I remember it just kind of ripping through the fabric of reality into a new world.”

Which was ironic because “Millionaire” had been rejected by multiple executives at multiple TV networks. Even when ITV finally bought it, not much was expected.

“No one thought it was going to do very well, but it ended up becoming the biggest game show in television history,” said playwright James Graham, who scripted “Quiz” — based on his play of the same title and the book “Bad Show: The Quiz, the Cough, the Millionaire Major” by Bob Woffinden and James Plaskett.

The thinking was that the format was too simple to succeed. The pitch to ITV executives was, “People love a good pub quiz, a uniquely British invention combining our two greatest loves — drinking and being right.”

What programmers didn’t anticipate was the drama and tension built into a show in which contestants had to risk a quarter of a million to win half a million, and then risk half a million to win a million based on their ability to come up with answers to trivia questions — and their confidence in their answers.

(Photo courtesy of Matt Frost/AMC) Matthew Macfadyen as Charles Ingram and Michael Sheen as Chris Tarrant in "Quiz."

Graham said he was “obsessed” with the show when it premiered in September 1998. “I just couldn’t believe how emotional it was,” he said. “The investment in people making these huge, life-changing decisions.”

It’s an amazing story … and, for most of the first two episodes of “Quiz,” the whole cheating scandal is pretty much tacked on to the more interesting behind-the-scenes story of “Who Wants to be a Millionaire?”

(By the way, the British version has a question mark in the title; the American version does not.)

The scandal erupted in September 2001 when Charles Ingram competed on “Millionaire” — despite the fact that both his wife and his brother-in-law had previously been contestants. (They each won 32,000 pounds.) Although Charles Ingram seemed baffled and confused by multiple questions — and suddenly changed his mind on several occasions — he won the big prize.

But producers became suspicious when his sudden changes seemed to follow coughs by either his wife or a fellow contestant, Tecwen Whittock, and called police. Which landed the Ingrams and Whittock in court.

It’s quite clear that Graham sympathizes with the defendants, but he doesn’t vilify the producers, the police or the prosecutors.

“The joy of the story for me, actually, is I don’t think there are any bad guys,” Graham said. “To this day, Paul Smith, the inventor of ‘Who Wants to be a Millionaire?,’ he still believes that they are guilty, and he believes that very passionately. He might be wrong, but he believes it.

“Similarly, the Ingrams are normal people who go through this extraordinary story where they’re thrown into the limelight. They’re made international laughingstocks, and they’re on trial for their freedom. They may get sent to jail if they’re found guilty. … We ask the audience to make up their minds about whether they’re innocent or guilty.”

Well, his thumb is clearly on the scale of justice, although “Quiz” equivocates on whether the Ingrams are guilty. But Graham’s teleplay makes it clear that he believes there was definitely cheating going on — a shadowy conspiracy that may or may not have involved the Ingrams.

“I discovered a whole network of obsessed quiz fans who … successfully hacked into the show,” Graham said. “It’s like the hole in the Death Star that Luke Skywalker found. It was the most valuable asset the network had, and there were these fundamental weaknesses that meant a certain network of very well-to-do, middle-class dweebs were allowed to find vulnerabilities into it and get their people on the show.”

He said these allegations had “never come to light, and we’re going to be revealing ... how successful they were.’”

(Photo courtesy of Matt Frost/AMC) Sian Clifford as Diana Ingram, Matthew Macfadyen as Charles Ingram and Michael Sheen as Chris Tarrant in "Quiz."

That’s in Episode 3, which focuses not only on the legal proceedings, but the extra-legal proceedings. The case makes major headlines, and the Ingrams are convicted in the court of public opinion. It didn’t help the real Ingrams that they didn’t come across as particularly likable people; it doesn’t help “Quiz” that they’re portrayed that way. As the three-parter nears its conclusion, it becomes less about their guilt or innocence than about “bigger questions about the nature of truth and justice in the 21st century,” Graham said.

And that makes for far less interesting television than the story of how “Who Wants to be a Millionaire?” took the world by storm.