For a show about a multiple-choice quiz, this miniseries about the cheating scandal that struck UK TV’s Who Wants to Be a Millionaire? is thrillingly, juicily open-ended. In 2001, bumbling Major Charles Ingram (Matthew Macfadyen) won the top prize with a sensational performance, but broadcasters ultimately decided to pull the episode from the air after noticing an apparently convenient pattern of coughing during taping.

Director Stephen Frears plunges us right into the nail-biting tension of Charles’ final questions; it feels as if we’re really watching live event TV. Macfadyen and Sian Clifford (as Charles' wife Diana, a former contestant herself) give masterfully cryptic yet human performances, while Helen McCrory (as their barrister) flips everything we thought we knew on its head in a showstopper of a courtroom scene. But the most impressive thing about Quiz is playwright James Graham’s writing: not only does the script play up the ultimate campiness of this intrigue (no one died, after all), but it also weaves in commentary on television’s appetite for “entertaining falsehoods.” What saves Quiz from feeling manipulative itself is how masterfully the mystery is balanced on a knife edge — it’s a stunning exercise in ambiguity that never stops being gripping, teasing us with its reminder that, sometimes, there is no final answer.

Episode one serves as an introduction to the Ingrams and a potted history of Who Wants to Be a Millionaire’s genesis, while the second is a thrilling immersion into the controversial episode itself and its immediate aftermath. The latter is also a sort of “case for the prosecution,” as the production staff’s suspicions are raised by several peculiarities in Charles’ performance (his tendency to choose an incorrect answer before suddenly switching to the right one, for example). As compelling as the show’s first two installments are, though, it’s episode three that proves to be its climax. McCrory lays out the case for the defense so convincingly — pointing out numerous gaping holes in the production's theory — that the broadcasters’ version of events is left in tatters by the end, completely destabilizing any certainty we might’ve felt. It’s a masterstroke of an episode, one that brings all of the show’s many threads into one satisfying — though still never conclusive — end.