Wendy loves cats, but her parents absolutely forbid her from having one. Luckily, her best friend Tina has a Siamese named Shal that she gets to see. While trying to work on her gymnastics, she falls, which gives this chick Nancy the chance to talk smack to her. Nancy is allergic to cats but knows that Wendy loves them and makes some crack about how she should take a lesson from them.
Tina and Wendy go to some cat show and check out the vendors area. Tina warns her that her mom told her not to buy any more cat crap, but she sees a cool little shop and wanders inside. The owner, Mrs. Bast, has everything cat you can name, and she has a display of jewelry and trinkets priced at $5. Wendy finds a really cool black cat pendant with a white spot on its face. Mrs. Bast grabs it from her, says it isn't for sale, and claims that it came from her private collection. She also warns them that it will turn the wearer into a werecat. Wendy waits until she's distracted, leaves a $5 bill on the table, and runs off with the necklace.
I bet you know where this is going, right? Wendy turns into a werecat that night. She loves how agile she is and how she can roam the streets. This happens a few more times, with her always coming home before her parents wake. The only downside is that she keeps running into a black werecat that tries to attack her and later attacks some other neighborhood cats.
Her school needs to pick the three best gymnasts to do some contest thing, and Wendy knows she isn't good enough. The night before, she sneaks into Nancy's house and rubs her cat body all over the other girl's clothes and bed. Nancy wakes up, freaks out, and almost kills her with an umbrella before opening the window and letting her out. The next day, Nancy is so bad at the competition to name the top gymnasts that she falls off the balance board and Wendy gets her spot.
After awhile, she decides that being a werecat really isn't that much fun. The only problem is that she can't get the necklace off. Tina tries everything, including her teeth, and can't get it off either. She tries looking for Mrs. Bast in the phonebook but she isn't listed. This all causes her to kind of resign herself to spending part of her life as a cat.
During a visit to Tina's house, Shal flips out when he sees Wendy and runs off. She feels herself changing and takes off, scratching the furniture on the way out, which Shal gets the blame for. She goes back on another day, and the cat manages to get away from them and run out the door. While trying to track him down, they see Mrs. Bast put him in a basket and take off. They follow her home and see her sprinkling stuff on him, which makes them think she's a witch.
Turns out that she's actually a cat groomer and it was cornstarch she put on him. It also turns out that it's not actually Shal but one of her clients. She shows Wendy the hidden clasp on the necklace and takes it off. Wendy tells her to keep the money and runs home thinking that it's all over. Oh, and they find Shal just chilling on the back porch when they get back.
Of course it's not really over. She turns into a cat again that night but tries to pretend it didn't happen. Wendy gets so anxious and excited about getting outside that she eventually throws herself through the glass window. Once outside, she sees a pack of werecats following her around. They start to attack but then rub all over her, and she realizes that they smell familiar.
Guess what? It's her mom, dad, and older brother. They're all werecats but didn't want to tell her until she was old enough. The necklace she stole was a charm that belonged to her family, and being around it caused her to change earlier. They never let her have a cat because cats and werecats are enemies. They all joke around and I guess it ends happily.
*Mrs. Bast just randomly picks up a cat off the street and takes it home to clean it. She explains that it belonged to one of her clients, but there has to be a better way to run your business.
*Wendy's dad rents a movie for her because it has cats in it. Why try to force your daughter to stop liking cats and then rent a cat movie?
*I don't care if you are a werecat, crashing through a solid glass window would hurt like the dickens. Wendy is totally okay five seconds later.