"Judith Potts is seventy-seven years old and blissfully happy. She lives on her own in a faded mansion just outside Marlow, there's no man in her life to tell her what to do or how much whisky to drink, and to keep herself busy she sets crosswords for The Times newspaper. One evening, while out swimming in the Thames, Judith witnesses a brutal murder. The local police don't believe her story, so she decides to investigate for herself, and is soon...

Catholic-schooled seventh-graders Sophie, Margaret, Rebecca, and Leigh Ann help an elderly neighbor solve a puzzle her father left for her estranged daughter twenty years ago.

Aubry Tourvel is 9 when she and her sisters, Pauline and Sylvie, stumble across a strange well in a courtyard secreted between empty apartment buildings. The well is made of smooth gray stone, and its opening has been carved to resemble a face. The siblings assume it's a wishing well, and because the papers are full of terrible news, each resolves to sacrifice something precious for the greater good. Pauline drops in a gold chain to stop the socialists...

Leo and Remi have gotten used to the strangeness of the Whippet Hotel, but when the entire top floor is hoisted into the sky and transported to the field of wacky inventions, they find that they must compete against a number of foes to solve a puzzle or lose their beloved hotel forever.

Working in secret for years to solve the puzzle in the writings of the 17th-century astronomer Johannes Kepler, Ivan Volkov, after the loss of his son and Russia's invasion of Ukraine, makes the fraught decision to contact the CIA, risking his life to help stop the Doomsday clock.

"Melissa is a nobody. Wilf is a slacker. Bondi is a show-off. At least that's what their middle school teachers think. To everyone's surprise, they are the three students chosen to compete for a ten thousand-dollar scholarship, solving clues that lead them to various locations around Chicago. At first the three contestants work independently, but it doesn't take long before each begins to wonder whether the competition is a sham. It's only by secretly...

"When Earth intercepts a message from a long-extinct alien race, it seems like the solution humanity has been waiting for. The Undying's advanced technology has the potential to undo environmental damage and turn lives around, and their message leads to the planet Gaia, a treasure trove waiting to be explored. For Jules Addison and his fellow scholars, the discovery of an ancient alien culture offers unprecedented opportunity for study... as long...

"Orphan Elizabeth Somers’s malevolent aunt and uncle ship her off to the ominous Winterhouse Hotel, owned by the peculiar Norbridge Falls. Upon arrival, Elizabeth quickly discovers that Winterhouse has many charms―most notably its massive library. It’s not long before she locates a magical book of puzzles that will unlock a mystery involving Norbridge and his sinister family. But the deeper she delves into the hotel’s secrets, the more Elizabeth...

2003, Colorado: Alexandra Solarin is summoned home to her family's ancestral Rocky Mountain hideaway for her mother's birthday. Thirty years ago, her parents, Cat Velis and Alexander Solarin, believed that they had scattered the pieces of the Montglane Service around the world, burying with them the secrets of the power that comes with possessing it. But Alexandra arrives to find that her mother is missing and that a series of strategically placed...