Desiree (Dez) is the one character in Nash Must Learn with whom Nash has the most history, the strongest emotion, and the deepest contention. Readers are introduced to Dez shortly after the opening segment where she and Nash are reunited for the first time in several years following a bitter fight. They are cousins and have fond memories of growing up together. Her attempts to act sunny and blithe are short-lived during the sentimental encounter as her emotions spill over upon seeing him again.

Much of the story will revolve around or involve Desiree in some way. Nash must learn how to fix what has been broken in their relationship and navigate through the potent, complex, and often-times conflicting mire of dynamic feelings and desires standing in the way of their reconciliation. Though she does not know it, Desiree walks a dangerous path and readers must direct Nash to either help her or let her walk alone.