If Miranda had an arch nemesis, it would be Julia, a fellow student who she actually says she "hates" (11.9). Much of the tension revolves around the class differences between the two characters. While Miranda's family is poor, Julia comes from a very privileged background. This crucial difference creates total friction between the girls. Miranda describes her first memory of Julia as follows:
My first memory of Julia is from second grade, when we made self-portraits in art. She complained there was no "café au lait" – colored construction paper for her skin, or sixty-percent-cacao-chocolate" color for her eyes. I remember staring at her while these words came out of her mouth, and thinking, Your skin is light brown. Your eyes are dark brown. Why don't you just use brown, you idiot? (11.10)
Miranda finds Julia's description of her features to be just plain obnoxious and pretentious. We later learn that Julia picked up her fancy words from her travels with her parents, which further annoys Miranda, leading her to give Julia the nickname "Swiss Miss."
As a person of color, Julia's race also plays an important role in the novel. Though her family is well off, she still experiences the effects of racism from Jimmy, the owner of the sandwich shop that Miranda and Annemarie work at during their lunch period.
After Miranda's transformation to a compassionate person in Chapter 41, Miranda calls a truce with Julia and tries to understand her a little better. She realizes that Julia cares very much about Annemarie. In her attempt to become friends with the girl, Miranda learns that Julia loves science and outer space (hinted at in her explanation of time travel as a diamond ring earlier in the book), and that her family life isn't as perfect as it might at first seem (her meditating mother is nowhere to be found).
As the novel ends, Miranda finds a drawing of a grown-up Julia beneath the mailbox of her apartment building, where the Laughing Man used to sleep. We find out that Julia will become Marcus's wife. Julia is the woman referred to when the Laughing Man says, "I'm an old man, and she's gone now" (53.11).