The Greenglass House (Green Glass House #1) by Kate Milford

It’s wintertime at Greenglass House. The creaky smuggler’s inn is always quiet during this season, and twelve-year-old Milo, the innkeepers’ adopted son, plans to spend his holidays relaxing. But on the first icy night of vacation, out of nowhere, the guest bell rings. Then rings again. And again. Soon Milo’s home is bursting with odd, secretive guests, each one bearing a strange story that is somehow connected to the rambling old house. As objects go missing and tempers flare, Milo and Meddy, the cook’s daughter, must decipher clues and untangle the web of deepening mysteries to discover the truth about Greenglass House. -MLN Catalog

Chasing Vermeer (Chasing Vermeer #1) by Blue Balliett

When strange and seemingly unrelated events start to happen and a precious Vermeer painting disappears, eleven-year-olds Petra and Calder combine their talents to solve an international art scandal. -MLN Catalog

The Parker Inheritance by Varian Johnson

Twelve-year-old Candice Miller is spending the summer in Lambert, South Carolina, in the old house that belonged to her grandmother, who died after being dismissed as city manager for having the city tennis courts dug up looking for buried treasure–but when she finds the letter that sent her grandmother on the treasure hunt, she finds herself caught up in the mystery and, with the help of her new friend and fellow book-worm, Brandon, she sets out to find the inheritance, exonerate her grandmother, and expose an injustice once committed against an African American family in Lambert. -MLN Catalog

When you Reach Me by Rebecca Stead

As her mother prepares to be a contestant on the 1980s television game show, “The $20,000 Pyramid,” a twelve-year-old New York City girl tries to make sense of a series of mysterious notes received from an anonymous source that seems to defy the laws of time and space. -MLN Catalog

Three Times Lucky (A Mo & Deal Mystery #1) by Sheila Turnage

Washed ashore as a baby in tiny Tupelo Landing, North Carolina, Mo LoBeau, now eleven, and her best friend Dale turn detective when the amnesiac Colonel, owner of a café and co-parent of Mo with his cook, Miss Lana, seems implicated in a murder. -MLN Catalog

The Westing Game by Ellen Raskin 

The mysterious death of an eccentric millionaire brings together an unlikely assortment of heirs who must uncover the circumstances of his death before they can claim their inheritance. -MLN Catalog

The Scandalous Sisterhood of Prickwillow Place by Julie Berry

Seven very proper Victorian young ladies conspire to hide a murder from the authorities at their boarding school. -MLN Catalog

Escape from Mr. Lemoncello’s Library (Mr. Lemoncello #1) by Chris Grabenstein 

Mr. Lemoncello holds a contest for his young friends where they must race to bring interesting facts back to his library. -MLN Catalog

The Book Scavenger (Book Scavenger #1) by Jennifer Chambliss Bertman

Just after twelve-year-old Emily and her family move to San Francisco, she teams up with new friend James to follow clues in an odd book they find, hoping to figure out its secrets before the men who attacked Emily’s hero, publisher Garrison Griswold, solve the mystery or come after the friends. -MLN Catalog

The Mysterious Benedict Society (Mysterious Benedict Society #1) by Trent Lee Stewart

After passing a series of mind-bending tests, four children are selected for a secret mission that requires them to go undercover at the Learning Institute for the Very Enlightened, where the only rule is that there are no rules. -MLN Catalog

Capture the Flag (Silver Jaguar Society #1) by Kate Messner

When the original Star Spangled Banner is stolen, seventh-graders Anne, José, and Henry, all descendants of the Silver Jaguar Society, pursue suspects on airport carts and through baggage handling tunnels while stranded at a Washington, D.C., airport during a snowstorm. -MLN Catalog

Loot (Loot #1) by Jude Watson

When Alfie McQuinn, the notorious jewel thief, is killed on a job, his last words to his son, March, are to “find jewels” and this instruction leads the boy to Jules, the twin sister he never knew he had–and the perfect partner to carry on the family business. -MLN Catalog

Absolutely Truly (Pumpkin Falls Mystery #1) by Heather Vogel Frederick

Twelve-year-old Truly Lovejoy’s family moves to a small town to take over a bookstore. Soon, she has to solve two mysteries involving a missing book and an undelivered letter. -MLN Catalog