Given the following context:  Andy is an aspiring journalist fresh out of Northwestern University. Despite her ridicule for the shallowness of the fashion industry, she lands a job as junior personal assistant to Miranda Priestly, the editor-in-chief of Runway magazine. Andy plans to put up with Miranda's excessive demands and humiliating treatment for one year in the hopes of getting a job as a reporter or writer somewhere else. At first, Andy fumbles with her job and fits in poorly with her gossipy, fashion-conscious co-workers, especially Miranda's senior assistant, Emily Charlton. However, she does find an ally in art director Nigel, and gradually learns her responsibilities and begins to dress more stylishly to show her effort and commitment to the position. She also meets an attractive young writer, Christian Thompson, who offers to help her with her career. As she spends increasing amounts of time at Miranda's beck and call, problems arise in her relationships with her college friends and her live-in boyfriend, Nate, a chef working his way up the career ladder. Miranda is impressed by Andy and allows her to be the one to bring the treasured "Book", a mock-up of the upcoming edition, to her home, along with her dry cleaning. She is given instructions by Emily about where to leave the items and is told not to speak with anyone in the house. Andy arrives at Miranda's home only to discover that the instructions she received are vague. As she tries to figure out what to do, Andy begins to panic. Miranda's twins, Caroline and Cassidy, falsely tell her she can leave the book at the top of the stairs just as Emily has done on many occasions. At the top of the stairs, Andy interrupts Miranda and her husband having an argument. Mortified, Andy leaves the book and runs out of the house.  answer the following question:  Whose ally is Nigel?
Andy