Andrea Sanchez (Anne Hathaway), who is new to society, comes to the famous fashion magazine "RUNWAY" for an interview. With her intelligence, she gets the permission of the editor-in-chief Miranda Presley (Meryl Streep) to serve as her second assistant. At the beginning, Andrea felt very aggrieved. No matter how hard she worked, she could not be appreciated. After the guidance of an old senior, she reshaped herself. The work went more and more smoothly, and even replaced the position of the first assistant in Miranda's heart. She decided to take this smart girl to France. But Andrea's change made her lose the love of her boyfriend and friends, which made her very conflicted. After arriving in France, she learned that Miranda's position was no longer secure. Unexpectedly, Miranda sacrificed her good partner of many years to save her position. This made Andrea deeply disappointed and had the idea of withdrawing. Where will Andrea go?