The Hall of Whispers. The Carousel Conspiracy, #1

For orphans Alex, Maya, and Leo, the world has been a cold place since their parents vanished years ago. Just as they hit rock bottom, they inherit a legacy they never knew existed: the Midnight Carnival, a sprawling, run-down lot of archaic rides left to them by a long-lost grandfather. But the rusty Ferris wheel and cracked Hall of Mirrors aren't just relics of the past-they are incredibly complex mechanical puzzles.
By solving the riddles hidden within the machinery, the siblings uncover a coded message revealing that their parents' disappearance was no accident. They have stumbled into a secret war against The Directorate, a shadowy global organization that manipulates free will from the darkness. To survive, they must unlock the secrets of each ride, learning that the funhouse mirrors and roller coaster drops are the only things standing between humanity and total control.