The X-Files meets Scooby-Doo in THE THIRTEENTH CIRCLE, a middle-grade mystery from MarcyKate Connolly and Kathryn Holmes, featuring two unexpected friends, crop circles, science fairs, and Men in Black, perfect for both the highly scientific and cryptid enthusiasts alike.

Cat knows aliens are real, and she's determined to prove it. By studying the Weston Farm Circles, her town's legendary crop circle phenomenon, she'll not only demonstrate the existence of extraterrestrial life, but also win the grand prize in the McMurray Youth Science Competition--a feat she's sure will impress her distant NASA scientist father.

Dani most certainly does not believe in aliens. How can she, when they go against every scientific principle she's been taught? So when Dani is paired with Cat to enter the McMurray Youth Science Competition--which she has to win to avoid going to her parents' artsy summer camp--she knows she's at a disadvantage. Her solution? Disprove Cat's theory, of course . . . without telling her partner her true intentions.

But as the girls bond over science, it becomes clear that there is something strange about the Weston Farm Circles. And when Dani and Cat's project is threatened by suspicious forces, they'll have to work together to expose the truth, once and for all.

MarcyKate Connolly is a New York Times bestselling children's book author who lives in New England with her family and a grumble of short-nosed dogs. She can be lured out from her writing cave with the promise of caffeine and new books. When she was in 4th grade, she and her neighbors saw an unidentified flying object zig-zag across the sky over their backyard and she's been preparing to write a book like The Thirteenth Circle ever since. She's also the author of several middle grade fantasy novels including Monstrous and the Shadow Weaver series, and a young adult duology (Twin Daggers and Heartless Heirs). You can visit her online at marcykate.com.

Kathryn Holmes is the author of multiple books for kids and teens, including the Class Critters chapter book series and the young adult novels The Distance Between Lost and Found and How It Feels to Fly. The Thirteenth Circle is her middle-grade debut. Kathryn grew up in Maryville, Tennessee, and now lives in Brooklyn, New York, with her husband, daughter, and piles upon piles of books. A graduate of The New School's MFA in Creative Writing program, Kathryn works as a freelance dance journalist, among other writing gigs. You can find her online at KathrynHolmes.com.