Spoiler warning: Spoilers for the entire film, including Helen’s identity and the final fire.
Helen destroys the Mona Lisa using Miles Bron’s own fuel, making his cherished legacy inseparable from catastrophe. The ending of Glass Onion finds another way to expose him after he burns the evidence that could establish her sister’s claim.
Who has been pretending to be Andi?
The woman on the island is Helen, Andi’s twin sister. She approaches Benoit Blanc after Andi’s death, then adopts her identity so they can investigate Miles’ circle.
The return to the earlier timeline reveals what Helen and Blanc knew during scenes the audience has already watched. Her unfamiliar behavior stops looking like a simple change in Andi’s personality: she is somebody else trying to hold the disguise together.
Andi’s claim concerns the company’s founding idea: the achievement Miles presents as his own. Her death protects both his ownership story and the status that depends on it.
Helen also survives the gunshot because Andi’s journal blocks it. Appearing dead gives her the chance to keep searching while Blanc occupies the guests.
Why does exposing Miles fail at first?
Miles killed Andi and then poisoned Duke to protect himself. But when Helen produces the evidence against him, he destroys it. Knowing the truth is not enough if everyone who could corroborate it remains dependent on him.
That dependence is the obstacle Blanc cannot solve through deduction alone. The guests’ livelihoods and ambitions have made silence useful. A correct explanation has to compete with their reasons for refusing it.
Why burn the Mona Lisa?
Helen uses Klear, the energy technology Miles is determined to promote, to ignite the destruction. His override of the painting’s safety system allows the fire to reach it.
The consequences strike the image he values most. He wanted his name spoken alongside the painting; now that association means responsibility for its destruction and a demonstration of his fuel’s danger.
In Netflix’s separate feature about the painting, Rian Johnson explains that he wanted the ending to belong to Helen’s victory while preserving ambiguity in her final expression. The cultural loss is not treated as something the audience can simply forget.
Helen gains leverage by making the damage public and impossible to separate from Miles’ choices. She has not obtained a shown courtroom verdict or brought Andi back. Instead, she has broken the protection his money and influence provided.
The last turn is fitted to this particular man: his ambition, unsafe product and personal vanity supply the means of his exposure. The reputation he designed to outlive him becomes the thing he can no longer control.
Sources: official ending breakdown; additional reporting and explanation.
More endings to unpack: The Prestige and Parasite.