‘Glass Onion’ Ending Explained: Who Is the Killer in ‘Knives Out 2’?

Detective Benoit Blanc is back on the case in Glass Onion: A Knives Out Mystery, aka Knives Out 2, which is now streaming on Netflix. And this case sure is a doozy, with plenty of twists, turns, and insufferable rich people who might have “dunnit.”

Written and directed by Rian Johnson, Glass Onion is an entirely new mystery for Detective Blanc, played once again by Daniel Craig. Blanc finds himself as a guest of a murder mystery party hosted by a tech billionaire. But when someone dies for real, suddenly everyone at the party becomes a suspect. Anyone of these big-name actors—including Edward Norton, Janelle Monáe, Kathryn Hahn, Leslie Odom Jr., Jessica Henwick, Madelyn Cline, Kate Hudson, and Dave Bautista—could be the killer!

But the two-hour 19-minute runtime is a long time to wait to figure out who dunnit. If you’re impatient, or if you got confused, don’t worry. Decider is here to help. Read on for the Glass Onion plot summary and the Glass Onion ending explained.

Warning: This article contains Glass Onion spoilers. Like, basically every spoiler for Knives Out 2 that you can possibly think of. You have been warned!

Do you have to watch Knives Out before Glass Onion?

No! Glass Onion is an entirely new mystery that is completely unrelated to the mystery in Knives Out, with an entirely new cast of characters. The only character and actor who is returning from the first movie is Daniel Craig as Benoit Blanc. You don’t need to see the first Knives Out movie to understand Knives Out 2.

Glass Onion plot synopsis:

Glass Onion introduces its cast of colorful characters by having each receive a puzzle box invitation to a murder mystery party from their mutual friend, a tech billionaire named Miles Bron (Edward Norton). There’s Claire (Kathryn Hahn), a politician who is hoping Miles will fund her campaign for Senate. There’s Lionel (Leslie Odom Jr.), a scientist at Miles’ company who has been asked to develop a new type of fuel called “Klear” that he knows is unstable and dangerous. There’s Birdie (Kate Hudson) a famous former supermodel who is prone to saying offensive things, and Birdie’s long-suffering assistant Peg (Jessica Henwick). There’s Duke (Dave Bautista), a Twitch streamer, and his way-too-young girlfriend Whiskey (Madelyn Cline).

And then there’s Andi, played by Janelle Monae. Everyone is shocked to see Andi there, given that Miles and co recently screwed her out of Miles’ tech company. The murder mystery party will be hosted on Miles’ private Greek island. And guess who also got an invite? The world’s greatest detective, Benoit Blanc (Craig). But, as Miles tells Blanc in a private aside, Miles actually didn’t invite Blanc to this party. The two conclude that someone must have reset the puzzle box and sent it to Blanc as a joke.

Miles invites Blanc to participate in the murder mystery, which he soon regrets—Blanc solves the case before the mystery has even begun. Blanc confesses to Miles he ruined the game on purpose because he suspects Miles’ life may be in danger. Blanc is seemingly proven right when Duke, after taking a sip of Miles’ drink, dies of poisoning.  Whiskey runs into the room crying, claiming Andi is the murderer. As part of the pre-planned murder mystery party, all of the lights go out. Chaos descends. Everyone is running around. Blanc meets up with Andi, and tells her she is the only one who can help solve this… and then a mysterious assailant shoots Andi.

What is the Glass Onion plot twist?

About halfway through the film, after “Andi” is shot, the film rewinds to the beginning. We reveal that was not, in fact, Cassandra “Andi” Brand who was screwed over by billionaire Miles Bron. It’s Andi’s twin sister, Helen. Showing off her considerable acting chops, Monae adopts a deep Southern accent and pays a visit to Benoit Blanc’s home in a prolonged flashback sequence.

Helen explains that her sister Andi supposedly committed suicide the week prior. But Helen believes Andi was murdered by one of her former so-called friends in Miles’ possé. Helen went through Andi’s email, and discovered an email she sent the day she died to all of the friends at the murder mystery party claiming she “finally found it, and I’m going to use it to burn this whole empire down.” Attached is a picture of Andi holding a red envelope. While cleaning out Andi’s place, Helen did not find the envelope, but she did find the puzzle box invitation. She brings the diary to Blanc, and the two of them hatch a plan to infiltrate the murder mystery party—with Helen posing as her sister and Blanc claiming to receive a surprise invitation—and uncover the real killer.

It’s soon revealed that the thing Andi found was the bar napkin in which she sketched out the idea for the company, Alpha, that Miles later took all the credit for creating. Andi and Miles were partners for years until Miles went all in on the idea for the new unstable hydrogen fuel. Andi put her foot down, on the grounds that it was dangerous. Andi leaves the company and tries to take the half that is rightfully hers, but Miles’ lawyers cut her out instead. That napkin key piece of evidence that was missing when Andi went to court to get back her share of the company. But the napkin went missing, and all of Miles’ friends testified in court that the company was his idea. Those ass-kissing, gold-digging liars! Also, Miles makes a fake version of the napkin he claims is his.

But Andi found the real napkin, and wrote that email to her ex-friends to let them know. And then someone murdered her. So while at the island pretending to be her sister, Helen looks everywhere for the red envelope with the napkin in it. She snoops around and discovers that everyone there has a motive for killing Andi, as well as the opportunity to do it. Shoot!

We learn the during the scene where Duke died, Helen was upstairs ransacking the rooms for the red envelope. Duke’s girlfriend Whiskey walks in on Helen while she’s trashing her room. Helen mistakenly thinks Whiskey is crying over breaking up with Duke, rather than him being dead, and tells Whiskey that Duke “deserved it,” which is why Whiskey believes Helen/Andi is the killer.

Helen meets Blanc outside, and we are finally caught up to the moment where the movie left off for all this flashback. Helen is shot but is protected from her sister’s diary in her jacket pocket. Blanc gets the idea to fake Helen’s death using Chekhov’s Jeremy Renner’s hot sauce as fake blood, and to inspire fake tears. This will buy Helen time to search the last room in the house—the glass onion—for the envelope. And she finds it.

Meanwhile, Blanc monologues downstairs and reveals that the killer is…

Who is the killer in Glass Onion?

It’s Miles Bron, aka the most obvious answer! Blanc proves that Blanc is stupid enough to kill Andi by pointing out how very dumb he is to say things like “inbreathiate,” and other dumb factual errors and verbal missteps. Miles Bron is not, Blanc concludes, the genius that everyone makes him out to be. No one tried to kill him. Miles killed Duke by purposefully handing him his glass, which Miles had poisoned. And Miles was also the one who killed Andi, by poisoning her tea when he stopped by for a visit, which is why he was so shocked to see “Andi” when she arrived on his island.

Glass Onion ending explained:

So why did Miles kill Duke? Because shortly before Duke’s death, Duke showed Miles an article on his phone about Andi’s suicide. Duke had seen Miles on the way to Andi’s house the night that Andi died. He didn’t realize Andi had died until he got a Google alert on his phone about her death, and he must have suspected that Miles killed her. Duke wanted to use that information to blackmail Miles to bolster his streaming career.  But Miles had a better idea: Give Duke a drink with pineapple juice in it, exploiting Duke’s deadly pineapple allergy.

And yes, that means it was also Miles who attempt to kill Helen, by stealing Duke’s gun and shooting her while the lights were out. (Which, incidentally, was an idea that Blanc gave him earlier in the film.) But now that Helen has the original napkin, she can prove he lied in court. How can she prove it’s the original? Because this napkin has the stamp from the name of the bar (also Glass Onion), which closed nine years ago. Miles’ napkin doesn’t have that stamp.

Not so fast, though. Miles uses his torch lighter to burn the napkin right there in front of everyone. Once again, no one is willing to stand up against Miles and testify that they saw him burn the napkin. Blanc sadly tells Helen there is nothing he can do without evidence. But he does offer her “some courage, and a reminder why your sister walked away in the first place.”

Huh? What does that mean? As it turns out, Blanc was subtly reminding Helen that Andi walked out because the hydrogen fuel that Miles had developed was essentially a bomb. And then he quietly slipped her the sample of that fuel that had been passed around earlier in the film  Helen trashes Miles’ belongings and lights a fire directly underneath the room’s air vent that leads straight up to the glass onion. Then she tosses in the hydrogen fuel. The glass onion explodes.

For her final “screw you” moment, Helen taps the button that removes the Mona Lisa’s protective glass, and the painting goes up in flames. She informs Miles that he got his wish, as he will always be remembered in the same breath as the Mona Lisa—as the man who destroyed the famous painting.

In the end, Miles and his friend don’t die. But the friends do say, at least, that they will back Helen in court, and will finally stop lying to protect Miles. In the film’s final scene, Blanc and Helen watch as the police boats come to shore. And with that, the movie ends. Cue The Beatles’ song “Glass Onion!”

Is there a Glass Onion post-credits scene?

No, there is no Glass Onion end-credits scene. Go to bed!