As Andy becomes indispensable to Miranda, she gradually outshines Emily. When Emily is struck by a taxi, Miranda forces Andy to deliver the news that Andy will be accompanying Miranda to Paris Fashion Week in Emily's place—warning Andy that refusing will derail her future journalism prospects.
In Paris, Andy learns through writer Christian Thompson that Elias-Clarke chairman Irv Ravitz plans to replace Miranda as Runway’s editor-in-chief with the younger, French editor Jacqueline Follet. Desperate to warn Miranda out of loyalty, Andy rushes to her hotel suite. The climax subverts expectations: during the celebratory luncheon, Miranda announces that Jacqueline has been named the new head of James Holt’s lucrative global fashion venture—the exact career-defining post Miranda had previously promised to her loyal art director, Nigel. Miranda reveals to Andy that she already knew about the coup and neutralized it by offering Jacqueline Nigel’s dream job, keeping her own editorial throne at Nigel's expense.
In the car afterwards, Miranda praises Andy, telling her: "I see a great deal of myself in you... you can see beyond what people want and what they need, and you can make choices for yourself." When Andy protests, "I could never do to anybody what you did to Nigel," Miranda cold-bloodedly responds that Andy already did the exact same thing to Emily by taking her place in Paris, concluding: "Everybody wants to be us."
Horrified to realize she is transforming into Miranda, Andy exits the car at Place de la Concorde. When Miranda calls her moments later, Andy stares at her vibrating phone and hurls it directly into the fountain, turning her back on Runway forever. Back in New York, Andy reconciles amicably with Nate, gifts her entire Paris wardrobe to Emily, and interviews at a respected publication (The New York Mirror). The interviewer reveals Miranda sent a fax stating that not hiring Andy would be the biggest idiot move they ever made. In the final scene, Andy spots Miranda on a Manhattan street; Andy gives a humble, knowing wave. Miranda ignores her publicly, enters her town car, and once inside the safety of tinted windows, removes her sunglasses and offers a subtle, genuine smile of respect before commanding her driver: "Go."