7 Friends Trapped On Island To Play Murder Mystery Game Till One Ends Up Dead - Baking A Mystery

The story begins in May 2020 during the pandemic. Various prominent figures—Governor Claire Debella, scientist Lionel Toussaint, and fashion designer Birdie Jay, along with influencer Duke Cody—receive elaborate puzzle boxes from billionaire Miles Bron. Each box, after solving several intricate puzzles, reveals an invitation to Miles's private island for a murder mystery weekend. Meanwhile, Cassandra 'Andi' Brand, Miles's estranged former business partner, angrily smashes her box. Detective Benoit Blanc, feeling restless during lockdown, also receives a mysterious box and, unlike the others, immediately accepts the invitation.

Blanc arrives in Greece, where the other guests, including Andi, are gathering. The group is surprised and tense, given Andi's recent legal battle with Miles. Lionel reveals to Blanc that Andi co-founded Alpha, Miles's tech giant, but was unfairly cut out of the company. Amidst an awkward reunion, they are all ferried to Miles's private island, dominated by his extravagant Glass Onion mansion. Miles explains that their rooms are assigned by chakra and accessed via unique wristbands that also serve as keys.

Miles singles out Blanc, expressing surprise at his presence, as he never sent him an invitation. Blanc reveals he received a re-set puzzle box from an anonymous sender, suggesting someone wanted him at the party. Miles realizes someone reset and sent him his unique invitation box as a joke. Later, at the pool, the guests discuss their individual connections to Miles, revealing how he financially or professionally bailed them out of various controversies. Andi exposes their collective dependency on Miles, revealing that each of them 'prostituted' themselves to him for personal gain, creating a tense atmosphere.

During cocktail hour, Miles dramatically showcases the Mona Lisa, currently on loan to him due to the Louvre's pandemic financial struggles. He then presents his new solid hydrogen fuel, 'Klear,' which he claims powers his entire island. Both Lionel and Claire express serious concerns about Klear's safety and untested nature. Miles then announces his murder mystery game, where he'll be the victim, challenging everyone to solve his staged murder. Blanc, unimpressed, quickly solves the 'murder,' exposing Miles's elaborate setup and the true motives of each guest to either protect or harm Miles due to their complex relationships.

As the party continues, Duke suddenly chokes and collapses, dying on the floor. Blanc quickly examines him, confirming a real murder. Miles panics, realizing Duke drank from his personalized glass. Lionel discovers Duke's gun is missing from his holster. Just as the hourly 'dong' sounds, the island's power goes out, plunging everything into darkness. Whiskey, Duke's girlfriend, hysterically accuses Andi of the murder. Miles flees, fearing he's the next target. Blanc encounters Andi outside, only for her to be shot by an unseen assailant. Blanc, realizing it's part of a larger scheme, feigns Helen's death to protect her and continue the investigation.

A flashback reveals that the person everyone believes to be Andi is actually Helen Brand, Andi's twin sister. Helen, a third-grade teacher, came to Blanc after Andi's apparent suicide, convinced it was murder. Andi had discovered a crucial document that could expose Miles and his friends' perjury during their trial, sending an email to them before her death. Helen hired Blanc to investigate, agreeing to impersonate Andi on the island. Blanc instructed Helen to gather information, leading to her discoveries about Whiskey's ambition, Claire and Lionel's compromised integrity regarding Klear, and Birdie's sweatshop scandal.

Helen realizes the group's alibis for the night of Andi's death are suspicious, as each of them visited Andi's house. Duke reveals that Miles denied him a spot on Alpha News, giving him a motive against Miles. Helen discovers Birdie's incriminating email approving sweatshop labor. Blanc and Helen deduce that the crucial envelope containing the original Alpha napkin, which would prove Miles's lies, must be hidden in Miles's office. Helen, feigning a dramatic outburst, creates a diversion to search Miles's Glass Onion office for the envelope. While Blanc distracts the others, Helen finds the napkin behind a framed fake one.

Blanc exposes Miles as a fraud and an idiot, revealing that Miles orchestrated Andi's murder by spiking her drink after she refused to back down. He killed Duke with a pineapple allergy after Duke discovered Miles's involvement in Andi's death, as revealed by a Google alert on Duke's phone. Blanc points out Miles's repeated usage of 'dumb luck' and taking credit for other people's ideas throughout his career. Helen, now revealed as Andi's sister, confronts Miles. She and the other guests, fed up with Miles's deceit, begin to destroy his glass sculptures. Helen throws a Klear crystal into the mansion's fire, causing a massive explosion that destroys the Glass Onion and the Mona Lisa.

As the mansion burns, Helen ensures the Mona Lisa, still within its protective case, is engulfed by the Klear-fueled fire. She then reveals to Miles that his 'fuel of the future' inadvertently destroyed the world-famous painting, effectively ruining his reputation and empire. The other guests, finally seeing through Miles's lies, corroborate Helen and Blanc's accusations. With their testimonies, the police, who are now arriving, have ample evidence to arrest Miles. Helen and Blanc watch from the shore, their mission accomplished, as the movie concludes with a song alluding to the deceptive nature of appearances.