Andrea Sanchez (Anne Hathaway), who has just entered society, came to the famous fashion magazine "RUNWAY" for an interview. With her cleverness, she was licensed by editor-in-chief Miranda Presley (Meryl Streep) to serve as her second assistant. At first, Andrea felt very wronged. No matter how hard she worked, she couldn't be appreciated. After the guidance of an old veteran, she transformed herself again. The work became more and more smooth, 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, making her very conflicted. After arriving in France, she learned that Miranda's status was in jeopardy. Unexpectedly, Miranda would sacrifice her good partner for many years to maintain her status. Andrea was deeply disappointed and had the idea of withdrawing and leaving. Where will Andrea go?