Colleen AF Venable and illustrator Stephanie Yue’s Katie the Catsitter (2021) is a middle-grade graphic novel about growing up, superheroes, and lots of cats. As of 2023, there are two additional volumes published in the series: Katie the Catsitter Book 2: Best Friends for Never (2022) and Katie the Catsitter #3: Secrets and Sidekicks (2023). Katie the Catsitter was critically well-received and has gone on to win multiple state awards.

In this coming-of-age story, Katie tries to earn enough money to attend summer camp with her friends by cat sitting for her upstairs neighbor, Ms. Lang. She quickly learns that it will not be a typical cat sitting job, as Ms. Lang has 217 highly intelligent cats with a propensity for getting into trouble. On top of this, Katie begins to suspect that Ms. Lang might be the notorious supervillain the Mousetress.

This guide refers to the 2021 Random House Graphic edition of the text.

Plot Summary

Katie breaks into her apartment because she has forgotten her keys. Once inside, she discovers there is no food for dinner and heads down to the bodega. While talking to Mr. B, the owner of the bodega, a news report about a fire at a nearby cosmetic factory plays in the background. The police chief claims the attack is the work of a supervillain. The Eastern Screech—New York’s most popular superhero—shows up but fails to realize the fire is related to the fact the factory practiced animal testing.

The next day, Katie is in class with her friends Bethany and Jess. While their teacher drones on about how great the Eastern Screech is, the girls talk about their plans for summer vacation. Bethany and Jess are going to summer camp, but Katie cannot afford to go. They suggest that Katie could go for just one week, instead of all four, and Bethany says her mom has even offered to pay for Katie. Katie rejects the offer, but decides she will try to earn the money herself by doing chores for people around her apartment building. She has very little success at first and becomes dejected when she has only earned one dollar in the final week of school.

Katie spends the first night of summer vacation at Bethany’s house. They dye their hair matching colors and promise to write one another every day. The next morning, Bethany leaves for camp and Katie resolves to earn the money she needs. She goes door to door looking for customers but has no luck. Later that day, she complains to Mr. B about her struggles. Ms. Lang, who lives a few floors above Katie, enters the store and overhears their conversation. She also sees how good Katie is with Mr. B’s cat and offers her a job cat sitting for her in the evenings, which Katie readily accepts.

When she arrives at Ms. Lang’s apartment that night, she is surprised to learn that Ms. Lang not only has 217 cats, but that the cats are all supremely intelligent and capable of doing things like using a computer, the TV remote, and the bathroom. Before she leaves, Ms. Lang informs Katie that everything in her apartment locks and unlocks by fingerprint scanners and gives Katie a key that accesses them. After Ms. Lang leaves, cats quickly start causing trouble and trash the apartment. Katie panics that she is going to be fired after the first night, but the cats clean up after themselves and ensure the apartment is back in perfect order before Ms. Lang comes home.

Over the next two weeks, Katie continues to cat sit for Ms. Lang. She tells Bethany and Mr. B about how troublesome the cats are, but they both think she is exaggerating and give her some tips on how to deal with them. After many nights of persevering and trying different strategies, she makes a breakthrough and gains the cats’ respect. During this time, Katie writes to Bethany nearly every day, and receives as many letters as she writes. There are also two more attacks on local businesses, each guilty of animal cruelty and abuse. The attacks are attributed to a supervillain called the Mousetress.

Based on some clues she finds around the apartment, Katie begins to suspect Ms. Lang may be the Mousetress, and writes to Bethany about it. However, the postcard is intercepted at the post office and passed along to the Eastern Screech. Bethany doesn’t respond for over a week and Katie begins to get upset. To distract herself, she visits The Wax Museum of Justice (a superhero museum) with her mom to see what she can learn about the Mousetress. She sneaks into the supervillain wing of the museum, which is not included in their tour, and is relieved when the statue of the Mousetress looks nothing like Ms. Lang.

A postcard from Bethany finally arrives. Bethany makes no mention of Katie’s previous postcard, only talks about this new boy she has a crush on. The postcard has none of the usual decorations, and is signed “Beth” rather than Bethany. Katie realizes that their friendship is falling apart and debates whether she even wants to go to camp anymore.

That night, Katie realizes that no one has actually seen the Mousetress, so the statue in the museum can’t possibly be accurate. She also considers that the Mousetress might not actually be evil, since the businesses and people she has been targeting are all guilty of animal abuse.

The next day, Katie attends Pickle Fest with her mom. Nearby, Ms. Lang is speaking at an animal rights protest. Katie goes over to say hello. She meets a girl named Marie and the two hit it off. That night, Ms. Lang doesn’t return home at her normal time. Katie turns on the news and discovers that the Eastern Screech has captured the Mousetress. The cats reveal a hidden lair that confirms Katie’s suspicions: Ms. Lang is the Mousetress. Encouraged by the cats, Katie puts on a Mousetress costume. They plan an escape mission that takes advantage of all the cats’ special skills.

When Katie and the cats arrive at the prison where the Mousetress is being held, there are more guards than expected, as well as the Eastern Screech. The cats distract the guards and help Katie take out the Eastern Screech. However, they are still unable to rescue Ms. Lang because her cell has a special lock that requires two keys to be used simultaneously. While Katie tries to figure out the locks, the police chief shows up and reveals that he knows the Mousetress isn’t a villain. He helps Katie unlock the doors, and everyone escapes safely.

The next day, Ms. Lang asks Katie to be her sidekick. Katie decides not to go to camp, and instead starts saving for veterinary school. She also becomes close friends with Marie and begins learning to skateboard. Mr. B tells Ms. Lang that he knew all along that Katie would make a good sidekick.