Receiving a desperate call from the Mancusi family, Jessi takes on an unusual sitting job caring for three dogs, five cats, two birds, a cage of hamsters, guinea pigs, fish, a snake, rabbits, and turtles.

When Kristy sees how much her little brothers and sisters want to play on a softball team, she organizes a ragtag team of her own. They may not be champions, with Jackie Rodowsky, walking disaster, on the team, but at least they have team spirit! Now Bart's Bashers have challenged Kristy's Krushers to a game. The Bashers really are lean and mean...but the worst part of it all is that Kristy has a giant crush on the Bashers' coach.

Visiting her father on the west coast, Dawn is tempted to stay with him when she enjoys the beach, Disneyland, and a wealth of healthy restaurants, but the homesick baby-sitter fears leaving her mother and all of her friends.

Mother's Day is coming up and the baby-sitters have the same problem they do every year: What do they get their mothers? Kristy, especially, wants to do something nice for her mom. Mrs. Brewer has been acting kind of strange and secretive lately, and Kristy's worried about her.... But then Kristy gets another one of her great ideas. Why don't the baby-sitters treat their moms - and the mothers of the kids they sit for - to a day off without any kids around? The BSC plans a gigantic baby-sitting party.

Claudia's not worried when she hears her newest baby-sitting charge, Betsy, is a great practical joker. After all, how much harm can one girl do? As it turns out - plenty! Claudia breaks her leg because of one of Betsy's mean jokes...and now she's talking about quitting the club. Baby-sitting might be too dangerous. The rest of the BSC decides that Betsy needs to be taught a lesson - and the joke war is on!

The members of the Baby-Sitters Club come to the rescue to help Mary Anne search for her beloved kitten, Tigger, who has suddenly vanished.

Mary Anne should never have thrown away that chain letter she got in the mail. Ever since she did, bad things have been happening - to everyone in the Baby-Sitters Club. With Halloween coming up, Mary Anne's even more worried - what kind of spooky thing will happen next? Then Mary Anne finds a new note in her mailbox: Wear this bad-luck charm, it says. Or else. Mary Anne has to do what the note says. But who sent the charm? And why send it to Mary Anne? If the BSC doesn't solve this mystery soon, their bad luck might never stop!

Jessi knows a secret language! She learned it from Matt Braddock, the BSC's newest charge. Matt's been deaf since birth, and he uses sign language to speak. Since Jessi is Matt's baby-sitter, she's been using sign language, too. Soon all the kids in Stoneybrook want to learn to sign...which keeps the baby-sitters busy. Jessi's the busiest of all: she working on another secret just for Matt. Will she be able to keep the secret and pull off her special event?

Claudia has a sad good-bye to make. Her grandmother, Mimi, has just died. Claudia understands that Mimi was sick for a long time, but she's still mad at her grandmother for leaving her. Who will help Claudia with her homework...and share "special tea" with her? 

Stacey's parents are getting a divorce. Stacey is sad and angry, and she has a big decision to make - stay in New York with her father, or move back to Stoneybrook with her mother.

Dawn and Mary Anne are finally stepsisters and also roommates. When they begin to get on each other's nerves, Dawn comes up with a solution which pleases everyone. 

Lately, it seems like each of the baby-sitters besides Dawn has been singled out...and she's a little jealous. But now it's Dawn's turn to shine: Mrs. Pike has asked her to help prepare Margo and Claire for the Little Miss Stoneybrook contest! Dawn's going to do everything she can to help her charges win, even if Margo's only talent is peeling a banana with her feet. But then Kristy, Mary Anne, and Claudia are helping Karen, Myriah, and Charlotte enter the contest, too. It's hard to tell whether the competition is fiercer at the pageant - or in the BSC!

Mallory Pike has always wanted to be a member of the Baby-Sitters Club - they're so much fun to be around, and she's practically a baby-sitter already. Now the club members have invited Mallory to a meeting. This might be her big chance! But the BSC isn't making it easy - they make Mal feel like a baby on a job, and make her take an impossible written test. Mallory's beginning to think she doesn't want to be a part of the BSC...or maybe she and her new friend Jessi should start a club of their own. It's time to show those baby-sitters what a couple of new girls can do!

Mallory and Claudia are helping Stacey unpack from her move back to Stoneybrook when they find an antique trunk in the McGill's attic. Stacey doesn't want the dusty thing, so she gives the trunk to Mallory...who finds an old diary at the bottom of it. The diary belonged to Sophie, a girl who lived in Stacey's house in the 1890s. As Mallory reads deep into Sophie's diary, she discovers a mystery on their hands to solve, because Stacey's house isn't big enough for her, her mom...and a family of ghosts! 

At long last, Dawn's mother and Mary Anne's father have decided to get married!