Kim Possible begins as Kim and her best friend and sidekick, Ron Stoppable, start Middleton High School where Kim must navigate an intimidating new social hierarchy. She is ready to tackle the challenge head-on, just as she has with everything else in life, but her confidence is shaken when she faces roadblocks at every turn—getting lost in the confusing hallways, being late to class and facing rejection during soccer tryouts from her frenemy, Bonnie. Kim's day starts to turn around when she and Ron meet and befriend Athena, a new classmate and Kim Possible superfan who is having an even worse day than Kim. With Kim's guidance and friendship, Athena transforms into the newest member of Team Possible. Soon, Athena starts to eclipse Kim just as the nefarious Drakken and Shego resurface in Middleton with a master plan to finally stop Kim. Now it is up to Team Possible—Kim, Ron, tech-genius Wade, new friend Athena and Rufus, a naked mole-rat that Ron meets along the way—to stop these super villains.
Kim's original mission outfit from the series can be seen among Kim's gadgets.
The origin of how Ron and Rufus meet is out of canon. In the film, Ron finds Rufus in a science lab where he lives in a terrarium for naked mole-rats, while in "A Sitch in Time", Ron buys Rufus at the Smarty Mart during his preteen years.