Glass Onion ending explained: Who was the killer?

The ensemble cast this time around features Edward Norton, Kate Hudson, Janelle Monae, and Dave Bautista among others (including a couple of high-profile cameos) while the setting is a futuristic mansion on a private Greek island, owned by tech billionaire Miles Bron (Norton).

As with the first film in the franchise, Johnson likes to keep the audience guessing – with a number of twists and turns throughout the runtime – and so if you've just reached the end of the film and still need a few questions answered, you can read on for the Glass Onion ending explained. Though beware as heavy spoilers lie ahead.

Glass Onion ending explained

Before we get into the nitty-gritty of the ending, it's probably best that we begin with a brief reminder of the set-up.

The film opens with Benoit Blanc (Daniel Craig) receiving an invitation to the Greek island home of an immensely wealthy tech entrepreneur named Miles Bron (Edward Norton), where he soon finds he's the only person on the guestlist not connected to Miles's inner circle.

That circle consists of his head scientist Lionel Toussaint (Leslie Odom Jr), Connecticut Governor Claire Debella (Kathryn Hahn), fashion designer Birdie Jay (Kate Hudson), and men's rights streamer Duke Cody (Dave Bautista), all of whom appear to be funded by Miles – which in turn ensures their loyalty to him.

The first twist occurs when Miles takes Blanc aside and informs him he actually hadn't invited him at all, and that therefore someone amongst the party had somehow engineered for him to be there. Miles initially assumes it's all a joke as part of the elaborate murder mystery-themed party game he is hosting, and so allows the detective to stay.

Anyway, Miles is preparing to launch a supposedly revolutionary new fuel called Klear – and is keen to press ahead with the launch despite warnings that it could be extremely dangerous. One of the fiercest critics of the fuel is Cassandra "Andi" Brand (Janelle Monae), the former CEO of the technology company Alpha which she founded with Miles, and most of the guests are surprised when she shows up on the island alongside them.

Anyway, on the first night of their stay – when Blanc has already easily deciphered Miles' carefully planned mystery game – Duke suddenly collapses to the floor and dies, which prompts understandable panic and a lot of fingers pointed at Andi.

The thing is, Andi is not actually Andi. As she reveals to Blanc, the person who is claiming to be Andi is actually her twin Helen Brand, who has been informed that her sister has mysteriously died and has come to the island to try and identify the culprit, enlisting the help of Blanc in the process. The news of Andi's death has not yet been made public and so Helen is posing as her sister and working against the clock to find the killer.

The key to all this, she assumes, is a cocktail napkin that dates back to the early days of the group's friendship, which proves that Andi had initially come up with the idea for Alpha. This had been unable to be used as evidence when Miles had won a lawsuit against Andi and forced her out of the company – with help from testimony from the other members of the inner circle – and Helen reckons that one of the others had found the napkin and killed Andi in order to prevent the truth from coming out and seeing them prosecuted for perjury.

Things take another turn when Helen appears to be shot, but she is saved thanks to a handily placed journal in her jacket pocket. Spotting a perfect opportunity, Blanc helps Helen fake her death and then gathers the remaining partygoers in Miles' art room where he presents his grand theory.

The truth, he explains, is that Miles had been responsible for both Andi's murder and Duke's. He killed the former when the napkin's existence was made clear to him by Lionel and then spiked Duke's drink with pineapple juice – to which he is allergic – after the latter had begun to cotton on.

You see, just before his death, Duke had received a Google alert informing him of Andi's death – and coupled with the fact he had previously seen him speeding away from Andi's house he puts two and two together and realises what had happened.

While Blanc has been explaining this, Helen has taken the opportunity to locate the key napkin, and she arrives in the room where the others are gathered to reveal her true identity – only for Miles to immediately grab the napkin and burn it, destroying the evidence.

This understandably sends Helen into a furious rage, and she begins destroying all of Miles' valuable art, eventually causing the mansion to explode due to the malfunctioning Klear, which has been powering the whole complex. Among the artworks to be ruined in the carnage is the Mona Lisa – which Miles had loaned from the Louvre – making true his wish to be "remembered in the same sentence as the Mona Lisa."

This all has the double whammy effect of ruining Miles' reputation and proving that Klear is dangerous, and so realising that it no longer benefits them to cover for him, the surviving members of the inner circle finally agree to side with Helen and testify against Miles – guaranteeing his downfall.

Glass Onion: A Knives Out Mystery is now streaming on Netflix. Sign up for Netflix from £6.99 a month. Netflix is also available on Sky Glass and Virgin Media Stream.

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