Julia "Jules" Argent was once Carmen Sandiego's partner and she still considers Carmen to be the best agent ACME ever had. Jules is experienced with Carmen Sandiego's methods and is full of facts. She keeps a journal to keep track of clues and apparently has a good sense of intuition.
Jules believes that "everyone" at ACME blamed her for Carmen leaving the organization. In fact, Carmen herself considers Jules to be "very opinionated" and claims this made her "a little difficult to work with," although she never specifically states whether this had anything to do with her leaving ACME.
Jules looks to be in her early twenties or so and has a vaguely Asian-esque appearance. She mentions owning a cat.