The Baby-Sitters Club Wiki
The Baby-Sitters Club Wiki

Mallory and the Mystery Diary is the 29th book in The Baby-Sitters Club series by Ann M. Martin.

Back Cover Summary[]

Mallory and Claudia are helping Stacey unpack from her move back to Stoneybrook when they find an antique trunk in the McGills' attic. Stacey doesn't want the dusty thing, so she gives the trunk to Mallory...who finds an old diary in the bottom of it.

The diary once 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. There may be ghosts that haunt Stacey's house!

The Baby-sitters have one big mystery on their hands to solve. Because Stacey's house isn't big enough for her, her mom...and a family of ghosts!


Mrs. Pike asks Mallory to take a tuna casserole over to Stacey’s house as a welcome-back present for Stacey and Mrs. McGill after returning from New York to Stoneybrook.

While at Stacey’s house, Mallory, Stacey and Claudia find an ancient trunk that is rich-colored, made from leather, and has brass fastenings. However Stacey doesn't want it in her attic since it is taking up too much space and Mrs. McGill suggests throwing it away until Mallory offers to keep it. Mallory then pays Bryon, Adam, and Jordan (the ten year old Pike triplets who are Mal’s brothers) $1 each to get the trunk to Mal’s bedroom.

The next day, Mal’s brothers ask if they can open the trunk, but Mallory won't allow them because she doesn't want to ruin the locks. Later that day at the Monday BSC meeting, Mallory informs the club on the trunk's progress, and Kristy suggests using dynamite to open the trunk. Finally on Friday afternoon, Mallory orders her triplet siblings to open the trunk with a hammer and wrench, and what she finds inside is amazing. Not only are there antique dresses, blouses, brooches, and books, but also the diary of Sophie, a twelve-year-old girl that lived in Stacey’s house during the year of 1894.

When Mallory begins to read deep into Sophie’s diary she discovers a mystery that haunts Stacey’s house. Sophie’s mom died two days after giving birth to Sophie‘s brother Edgar, and three days after her mom was buried, a portrait of her disappeared from Sophie’s grandfather‘s house. Sophie’s grandfather is also known as Grandfather Hickman or Old Hickory who was the meanest, richest person in Stoneybrook and is rumored to haunt the Stoneybrook Cemetery. Grandfather Hickman accused Jared (Sophie’s dad) of stealing the painting and everyone believed him since Jared is known for his shady past and being arrested twice. As a result of this, Hickory wrote Sophie, Edgar, and Jared out of his will and stopped lending them money.

The last entry in Sophie’s diary was written on December, 31, 1894.

I vow clear my fathers name. If I cannot do that, then I am certain that when he and I do eventually die, our spirits will remain in the house, uneasy, unable to rest. My only hope is that little Edgar shall grow up untainted.

In the next meeting of the Baby-sitters Club Mallory asks Stacey if she has seen anything weird. She denies this but does say that she once saw something white in her room at the foot of her bed but isn’t sure if it is just moonlight.

On a Friday meeting of the Baby-sitters Club Mallory decides to hold a séance in order to contact the spirit of Sophie speaking through Kristy in a wavery, eerie voice. Kristy says at the end of the séance though, that she can‘t get Sophie to speak through her and only a crazy goon would think that to Mallory.

The century-old mystery is finally solved when Mallory shows Buddy the trunk, and Buddy’s hand gets caught in the pocket of it and he then finds papers of Old Hickory’s confession. They find out that after his daughter died he was distraught and couldn’t bear to look at her portrait but didn’t want to get rid of it so he hired an itinerant painter to paint ships over the painting. After that Hickory’s friends wanted to know where the portrait was so since Hickory was embarrassed about what he had done he lied and said the painting had disappeared and had probably been stolen. Immediately the townspeople suspected Jared.

After Stacey‘s mom got the painting from the art restorer the McGill’s decided to hang the painting in the living room by the mantelpiece since they wanted to reunite the portrait of Sophie’s mother, with the spirits of Sophie and Jared.

But no one knows if the house is still haunted...


Buddy Barrett's teacher Mr. Moser, sent home a note saying that his reading level was below grade level, which makes Mrs. Barrett upset at herself for not having enough time to run the household, go to work, and spend quality time teaching her kids. Later Mallory gets a steady job tutoring Buddy and Buddy’s reading level moves from the Crows (lowest reading group) to the Robins (average-middle reading group.)

-Meanwhile, at the Thomas-Brewer household, Kristy dares her brother David Michael, stepsister Karen, stepbrother Andrew, and adopted sister Emily Michelle to look into the attic on the fourth floor which Karen is convinced is haunted. While in the attic, they play hide-and-seek and don’t discover anything out of the ordinary but Karen claims that it was because it wasn’t night.


Mallory's Family

BSC Members





  • Pike House
  • McGill House
  • Barrett House
  • Thomas/Brewer House
  • Johanssen House

Pop Culture and Real-Life References[]

  • Nancy Drew
  • Miss Marple
  • Sesame Street
  • Green Eggs in Ham, The Bobbsey Twins, A Tree Grows in Brooklyn, Katie and the Sad Noise, The BFG, Encyclopedia Brown (books)
  • Pee-Wee's Playhouse
  • Candy Land, Chutes and Ladders, Memory, Dominoes (games)
  • Archie comics
  • Crime Court

Continuity and Inconsistencies[]



  • Mallory says that she and Jessi don’t mind being junior officers. But in most of the other books, it’s said that Mallory and Jessi complain about not being allowed to babysit at night.

Ann M. Martin's Dear Reader Letter[]

Dear Reader,

I have never been a diary or journal keeper, but when I was young—in fact, starting on the day I was born—my mother kept a diary for me. I love looking back through the diary to find out all sorts of things—what my first day of school was like, when I (finally) learned how to ride a two-wheeler, or simply what I did on June 10, 1958. I’m so glad my mother kept a diary for me, but I wish I had kept one for myself, too.

A journal isn’t necessarily exciting or thrilling, but it’s interesting because it’s about you. It’s also a great source of story ideas. Lots of kids tell me that they love to write, but they don’t know what to write about. I tell them that the best things to write about are things that have actually happened. And what better place to keep track of things that have happened to you than in your very own journal? Remember, it’s the story of your life. And only you can tell it.


  • A reprint is scheduled to be released September 3, 2024. [1]
  • On the dedication page it says "For Mary Dietrich and Virginia Kilbourne who taught me to respect children."
  • Mallory has never been in the house that Stacey lives in despite living right behind it.
  • People left things behind in the attic for years.
  • The BSC has learned that it's not a good idea to let Marnie eat or drink anything in a room with a rug in it.
  • Six couples/families had moved in and out of the house that Stacey moved into in the past twelve years.
  • This is one of the few books were the Brewer/Thomas kids explore the fourth floor of their house.
  • Stacey doesn't believe in the supernatural, astrology, or anything like that.
  • Kristy wears a skirt in this book.
  • Sittings jobs that were arranged but never seen include the Perkins, Arnolds, and Marshalls.
  • Some stuff in Stacey's attic includes:
    • World War 1 helmet
    • Paintings
    • Box of magic tricks (Stacey gives them to Buddy)
    • Music box
  • Mrs. McGill might believe in ghosts after hearing the story.
  • Richard and Sharon have been on twenty-five dates since they met again in Mary Anne Saves the Day.
  • James Hickman's house is still standing.


Baby-Sitters Club Books
The Summer Before | #1 Kristy's Great Idea | #2 Claudia and the Phantom Phone Calls | #3 The Truth About Stacey | #4 Mary Anne Saves the Day | #5 Dawn and the Impossible Three | #6 Kristy's Big Day | #7 Claudia and Mean Janine | #8 Boy-Crazy Stacey | #9 The Ghost at Dawn's House | #10 Logan Likes Mary Anne! | #11 Kristy and the Snobs | #12 Claudia and the New Girl | #13 Good-bye Stacey, Good-bye | #14 Hello, Mallory | #15 Little Miss Stoneybrook... and Dawn | #16 Jessi's Secret Language | #17 Mary Anne's Bad-Luck Mystery | #18 Stacey's Mistake | #19 Claudia and the Bad Joke | #20 Kristy and the Walking Disaster | #21 Mallory and the Trouble with Twins | #22 Jessi Ramsey, Pet-sitter | #23 Dawn on the Coast | #24 Kristy and the Mother's Day Surprise | #25 Mary Anne and the Search for Tigger | #26 Claudia and the Sad Good-bye | #27 Jessi and the Superbrat | #28 Welcome Back, Stacey! | #29 Mallory and the Mystery Diary | #30 Mary Anne and the Great Romance | #31 Dawn's Wicked Stepsister | #32 Kristy and the Secret of Susan | #33 Claudia and the Great Search | #34 Mary Anne and Too Many Boys | #35 Stacey and the Mystery of Stoneybrook | #36 Jessi's Baby-Sitter | #37 Dawn and the Older Boy | #38 Kristy's Mystery Admirer | #39 Poor Mallory! | #40 Claudia and the Middle School Mystery | #41 Mary Anne vs. Logan | #42 Jessi and the Dance School Phantom | #43 Stacey's Emergency | #44 Dawn and the Big Sleepover | #45 Kristy and the Baby Parade | #46 Mary Anne Misses Logan | #47 Mallory on Strike | #48 Jessi's Wish | #49 Claudia and the Genius of Elm Street | #50 Dawn's Big Date | #51 Stacey's Ex-Best Friend | #52 Mary Anne + 2 Many Babies | #53 Kristy for President | #54 Mallory and the Dream Horse | #55 Jessi's Gold Medal | #56 Keep Out, Claudia! | #57 Dawn Saves the Planet | #58 Stacey's Choice | #59 Mallory Hates Boys (and Gym) | #60 Mary Anne's Makeover | #61 Jessi and the Awful Secret | #62 Kristy and the Worst Kid Ever | #63 Claudia's Freind Friend | #64 Dawn's Family Feud | #65 Stacey's Big Crush | #66 Maid Mary Anne | #67 Dawn's Big Move | #68 Jessi and the Bad Baby-sitter | #69 Get Well Soon, Mallory! | #70 Stacey and the Cheerleaders | #71 Claudia and the Perfect Boy | #72 Dawn and the We Love Kids Club | #73 Mary Anne and Miss Priss | #74 Kristy and the Copycat | #75 Jessi's Horrible Prank | #76 Stacey's Lie | #77 Dawn and Whitney, Friends Forever | #78 Claudia and Crazy Peaches | #79 Mary Anne Breaks the Rules | #80 Mallory Pike, No. 1 Fan | #81 Kristy and Mr. Mom | #82 Jessi and the Troublemaker | #83 Stacey vs. the BSC | #84 Dawn and the School Spirit War | #85 Claudia Kishi, Live From WSTO! | #86 Mary Anne and Camp BSC | #87 Stacey and the Bad Girls | #88 Farewell, Dawn | #89 Kristy and the Dirty Diapers | #90 Welcome to the BSC, Abby! | #91 Claudia and the First Thanksgiving | #92 Mallory's Christmas Wish | #93 Mary Anne and the Memory Garden | #94 Stacey McGill, Super Sitter | #95 Kristy + Bart = ? | #96 Abby's Lucky Thirteen | #97 Claudia and the World's Cutest Baby | #98 Dawn and Too Many Sitters | #99 Stacey's Broken Heart | #100 Kristy's Worst Idea | #101 Claudia Kishi, Middle School Dropout | #102 Mary Anne and the Little Princess | #103 Happy Holidays, Jessi | #104 Abby's Twin | #105 Stacey the Math Whiz | #106 Claudia, Queen of the Seventh Grade | #107 Mind Your Own Business, Kristy! | #108 Don't Give Up, Mallory! | #109 Mary Anne to the Rescue | #110 Abby the Bad Sport | #111 Stacey's Secret Friend | #112 Kristy and the Sister War | #113 Claudia Makes Up Her Mind | #114 The Secret Life of Mary Anne Spier | #115 Jessi's Big Break | #116 Abby and the Best Kid Ever | #117 Claudia and the Terrible Truth | #118 Kristy Thomas, Dog Trainer | #119 Stacey's Ex-Boyfriend | #120 Mary Anne and the Playground Fight | #121 Abby in Wonderland | #122 Kristy in Charge | #123 Claudia's Big Party | #124 Stacey McGill... Matchmaker? | #125 Mary Anne in the Middle | #126 The All-New Mallory Pike | #127 Abby's Un-Valentine | #128 Claudia and the Little Liar | #129 Kristy at Bat | #130 Stacey's Movie | #131 The Fire at Mary Anne's House
Super Specials
#1 Baby-sitters on Board! | #2 Baby-sitters' Summer Vacation | #3 Baby-sitters' Winter Vacation | #4 Baby-sitters' Island Adventure | #5 California Girls! | #6 New York, New York! | #7 Snowbound | #8 Baby-sitters at Shadow Lake | #9 Starring the Baby-sitters Club #10 Sea City, Here We Come! | #11 The Baby-sitters Remember | #12 Here Come the Bridesmaids! | #13 Aloha, Baby-sitters! | #14 BSC in the USA | #15 Baby-sitters' European Vacation
Portrait Collection
Stacey's Book | Claudia's Book | Dawn's Book | Mary Anne's Book | Kristy's Book | Abby's Book
The Baby-Sitters Club Notebook (1987) | The Baby-Sitters Club Postcard Book (1991) | Trivia & Puzzle Fun Book (1992) | Ann M. Martin: The Story of the author of the Baby-sitters Club (1993) | The Baby-Sitters Club Guide to Babysitting (1993) | The Baby-Sitters Club Chain Letter (1993) | The Baby-Sitters Club Secret Santa (1994) | Audio Books on Cassette Tape (1994-5) | BSC Movie Novelization (1995) | The Complete Guide to the Baby-Sitters Club (1996) | Autograph Book (1998) | BSC Graphic Novels (2006-present) | We Are the Baby-Sitters Club: Essays and Artwork from Grown-Up Readers (2021) | Welcome to Stoneybrook: A Guided Journal (2021) | The Official Coloring Book (2023)