Sign-In
Cart
The Case of the Library Lock-In Secret: The Anna & Ava Detective Agency, Book 12
Paperback
Series: The Anna & Ava Detective Agency, Book 12
Chapter BooksGeneral Juvenile Fiction
Publisher: Independently Published
Published: Mar 23 2026
Pages: 92
Weight: 0.26
Height: 0.22 Width: 5.50 Depth: 8.50
Language: English
Locked in overnight.
A missing key.
And a secret hidden behind the shelves.
When Anna and Ava attend a library lock-in, the night takes an unexpected turn when a historic brass key disappears from a display case-without a single sign of damage.
No broken glass.
No forced entry.
Just one careful removal.
As the library doors lock for the night, the suspects are limited-but the mystery grows deeper. A shifted bookshelf. A hidden door. And a truth someone isn't ready to share.
But Anna and Ava don't guess.
They confirm.
In this thoughtful mystery, the sisters uncover more than what was taken-they discover why it was taken, and how even good intentions can create confusion when the full story isn't told.
Perfect for readers ages 7-12 who love:
- Smart girl detectives
- Realistic mysteries in familiar places
- Stories about truth, trust, and teamwork
Because sometimes solving the case...
means understanding the story behind it.
Also from
Patrick, Michael Paul
The Case of the Stolen Banner: The Anna & Ava Detective Agency, Book 11
Patrick, Michael Paul
Paperback
The Case of the Missing Library Book: The Anna & Ava Detective Agency, Book 1
Patrick, Michael Paul
Paperback
The Case of the Vanishing Field Trip Money: The Anna & Ava Detective Agency, Book 4
Patrick, Michael Paul
Paperback
The Case of the Phony Permission Slip: The Anna & Ava Detective Agency, Book 8
Patrick, Michael Paul
Paperback
The Case of the Suspicious Substitute: The Anna & Ava Detective Agency, Book 10
Patrick, Michael Paul
Paperback
The Case of the Unsent Invitation: The Anna & Ava Detective Agency, Book 9
Patrick, Michael Paul
Paperback
The Case of the Midnight Locker Note: The Anna & Ava Detective Agency, Book 5
Patrick, Michael Paul
Paperback
The Case of the Deleted Messages: The Anna & Ava Detective Agency, Book 7
Patrick, Michael Paul
Paperback
The Case of the Broken Trophy: The Anna & Ava Detective Agency, Book 3
Patrick, Michael Paul
Paperback
The Case of the Disappearing Class Pet: The Anna & Ava Detective Agency, Book 6
Patrick, Michael Paul
Paperback
The Case of the Secret Science Fair Sabotage: The Anna & Ava Detective Agency, Book 2
Patrick, Michael Paul
Paperback
Also in
General Juvenile Fiction
Percy Jackson and the Olympians, Book One the Lightning Thief (Percy Jackson and the Olympians, Book One)
Riordan, Rick
Paperback
The Truth about Stacey: A Graphic Novel (the Baby-Sitters Club #2): Full-Color Edition
Martin, Ann M.
Paperback
Dawn and the Impossible Three: A Graphic Novel (the Baby-Sitters Club #5): Full-Color Edition Volume 5
Martin, Ann M.
Paperback
Kristy's Great Idea: A Graphic Novel (the Baby-Sitters Club #1): Full-Color Edition
Martin, Ann M.
Paperback
Anne of Green Gables, 3-Book Box Set, Volume I: Anne of Avonlea; Anne of the Island; Anne of Green Gables
Montgomery, L. M.
Paperback
Percy Jackson and the Olympians: Sea of Monsters, The: The Graphic Novel
Riordan, Rick
Venditti, Robert
Paperback
Mary Anne Saves the Day: A Graphic Novel (the Baby-Sitters Club #3): Full-Color Edition
Martin, Ann M.
Paperback
Claudia and Mean Janine: A Graphic Novel (the Baby-Sitters Club #4): Full-Color Edition
Martin, Ann M.
Paperback
Captain Underpants and the Sensational Saga of Sir Stinks-A-Lot (Captain Underpants #12)
Dav Pilkey
Hardcover
Percy Jackson and the Olympians, Book Three the Titan's Curse (Percy Jackson and the Olympians, Book Three)
Riordan, Rick
Paperback
Rowley Jefferson's Awesome Friendly Spooky Stories 2: From the Creator of Diary of a Wimpy Kid
Kinney, Jeff
Hardcover
Dog Man: Big Jim Believes: A Graphic Novel (Dog Man #14): From the Creator of Captain Underpants
Pilkey, Dav
Hardcover
Harry Potter and the Half-Blood Prince: The Illustrated Edition (Harry Potter, Book 6): Volume 6
Rowling, J. K.
Hardcover
Wings of Fire: The Dragonet Prophecy: A Graphic Novel (Wings of Fire Graphic Novel #1)
Sutherland, Tui T.
Paperback
Investigators: Agents of S.U.I.T.: Sew Much Trouble
Hastings, Christopher
Green, John Patrick
Hardcover
Dog Man: The Scarlet Shedder: A Graphic Novel (Dog Man #12): From the Creator of Captain Underpants
Pilkey, Dav
Hardcover