Newly paroled Debbie Ocean, the late Danny Ocean's younger sister, convinces former partner-in-crime Lou to join her in a new heist. They assemble their team: bankrupt fashion designer Rose Weil, who is in debt to the IRS; jewelry maker Amita, who is eager to move out of her mother's house; security hacker Nine Ball (Rihanna); street hustler and pickpocket Constance; and profiteer Tammy, who fences stolen goods out of her suburban home.
Debbie plans to steal the Toussaint, a $150 million Cartier necklace, during the upcoming Met Gala and use beautiful film star Daphne Kluger as an unwitting accomplice. The team manipulates Daphne into hiring Rose and convinces Cartier to loan Daphne the Toussaint. They digitally scan the necklace to manufacture a worthless cubic zirconia replica. Tammy secures a job at Vogue and gains access to the gala and also gets Lou hired as a nutritionist while Debbie leads Daphne to invite art dealer Claude Becker, whose betrayal sent Debbie to prison, as her date. Lou confronts Debbie for planning revenge against Becker, but Debbie reassures her that it will not jeopardize their plan.