Laure Ash (REBECCA ROMIJN-STAMOS) is an alluring thief who's plotting a daring jewelry heist at the 2001 Cannes Film Festival with her partners, Black Tie (ERIQ EBOUANEY) and Racine (EDOUARD MONTOUTE). The plan is for Laure to seduce Veronica (RIE RASMUSSEN), one of the attendees, and replace her various diamond-studded accouterments with fake duplicates.
When a security official interrupts the heist, things turn violent and Laure hits the road with the diamonds. She thinks she's double-crossed the others, but another encounter with Racine ends up with her being thrown down into an atrium where she's knocked unconscious. An older couple who's followed her then mistakes her for their grieving daughter, Lily, who's recently lost her husband and child.
Laure then decides to adopt that woman's identity and head for America when she meets Watts (PETER COYOTE), a sympathetic American government worker. She thinks she's made a clean getaway, but seven years later, she returns as Watt's wife when he's made the American Ambassador to France.
It's then and there that former paparazzo Nicolas Bardo (ANTONIO BANDERAS) is assigned to get photos of the little seen wife. His actions eventually involve Serra (THIERRY FREMONT), a local French police inspector, Leonard Shiff (GREGG HENRY), head of Watts' security, and Black Tie and Racine who still want their diamonds.
From that point on, Laure/Lily sets an elaborate plan into motion that she hopes will take care of her various problems and predicaments.