I’m rewatching Kim Possible at the moment, after being away from it for several years, and I’m delighted to find it’s even better than I remember it. It’s not quite in the same league as Phineas and Ferb or My Little Pony, but it is a very solid, very entertaining show anchored by two particularly great leads.

It’s also instructive on how to write an absurdly capable character without her turning into a Mary Sue.

First some definitions: a Mary Sue is a character who is unrealistically perfect, whom all the good characters like, who never has to seriously struggle, and whom the audience is really, really supposed to admire. A textbook example would be Rey from The Force Awakens: the girl who can fly the Millennium Falcon, shoot a blaster, and wield a lightsaber better than anyone even with zero training or experience and who has no flaws to speak of, never seriously fails at anything, and who has everyone from Han Solo to the villain gushing with admiration over her.

Now, Kim Possible, the girl who “can do anything” seems like she would be a classic case of a Mary Sue. She’s a beautiful, popular cheerleader who saves the world as a hobby, has climbed Mt. Everest, swam the English Channel, and maintains a perfect GPA. She frequently saves her loser male sidekick, Ron Stoppable, and has a long rolodex of incredible feats.

But the thing is, Kim isn’t a Mary Sue. On the contrary, despite her exaggerated abilities, she’s a very likable, very believable character. One of the ways they do this is that Kim’s feats, impressive though they are, are limited. She can perform fantastic acrobatics and kung-fu fighting moves, but she still has to put up with things like detention, unpleasant fellow students, and getting butterflies while talking to cute boys. She faces instances of temptation and doesn’t always do the right thing, e.g. when she lies to both Ron and her parents in order to go a party where her crush is attending.

Basically, Kim’s ability to excel doesn’t mean that her life is perfect, or that she herself is perfect. It’s simply a fact about her, like the color of her hair. She still has to make the right choices and still has to deal with day-to-day problems. For instance, Kim’s school rival is the smug Bonnie, who never misses a chance to insult or belittle her. But since they’re both on the cheer-squad, Kim still has to try to get along with her as well as she can.

Likewise, Kim is shown to have clear flaws: she’s very competitive, kind of vain, and a bit of a snob. There’s an episode where she takes over coaching a ten-year olds’ soccer team and drives them so hard that they start crying when she shows up. Not only are these real flaws, ones that cause problems for her and others, but they’re very believable ones for someone of her personality type to have. And, despite her assertions, Kim can’t do anything: she’s a terrible cook, gets very irritated over mundane tasks, and becomes a mess when she gets nervous.

In short, Kim’s not always right, not always on top, and doesn’t always excel. She experiences failure, disappointment, and frustration. She makes mistakes and has to deal with the consequences.

Perhaps most surprising of all, given the evident feminist bent of the show, is how much she needs Ron’s help. It’s true she often has to save him, but that doesn’t mean that Ron is simply useless. On the contrary, he’s often the key to saving the day, and occasionally gets to go on his own adventures. Not only that, but the show repeatedly makes the point that Ron is a major factor in Kim’s success, and that her crime fighting is severely handicapped without him. Best of all, he periodically has to rescue her. Basically, for all that Kim is the star, Ron is really just as important to the story as she is (in some ways more so: his character arc is much more pronounced than hers, so that the show could almost be thought of as more Ron’s story than Kim’s).

Beyond that, they balance each other’s characters very well: she’s an overachiever, he’s an underachiever. She prods him to get serious and work hard, he prods her to relax and have a little perspective. The result is that they have a very charming, very believable relationship: a close friendship that grows into romance over the course of the series, and which culminates in Ron coming into his own as a hero in order to save Kim (it’s honestly a very cool progression and my favorite aspect of the show).

Does any of this make Kim less admirable or less of a role model? On the contrary, it makes her much, much more so. If she simply excelled at everything and was always on top of things, she’d be insufferable. The fact that she does have to struggle, does have to face up to her own flaws, and does sometimes need help makes more human and consequently more likable. Her relationship with Ron, and with it the fact that she isn’t completely self-sufficient, puts her incredible abilities in a human context and gives both her and Ron room to grow as characters.

Kim is really a textbook example of how to avoid making a character a Mary Sue: she can be as absurdly capable as you like, but let her have flaws, let her make mistakes, and above all, have her need someone. In short, let her be a little vulnerable and a little human.