The Vanishing Benefactor. The Maple Ridge Inheritance, #5

When a convoy of electric vans rolls into Riverview's abandoned riverside mill, Tessa Caldwell thinks it's just another oddity in a summer already full of them. But the new arrival-Dr. Elias Rourke, a reclusive tech inventor rumored to be sitting on millions in prototypes-brings more questions than answers. His workers speak in hushed tones, his equipment arrives in reinforced cases, and the mill's brand-new security cameras point away from the building, scanning the woods instead of guarding the doors.
Something about it feels wrong. That feeling becomes impossible to ignore when Mira Rourke, the inventor's niece, arrives at Crabapple Farm with a single chilling truth: her uncle has vanished, and no one is looking for him. The police dismiss her concerns. Her parents insist everything is fine. But Mira carries a coded message slipped secretly into her bag-one written in a cipher Jake Grayson recognizes from his great-uncle's hidden papers.
Someone wanted Mira to find it. Someone wanted her to run. Tessa, Harper, Jake, and Benny follow the clues into the mill, uncovering a hidden lab sealed behind a false wall. Inside lie custom processors, encrypted monitors, and the shattered remains of a drone whose missing memory card hints at a violent encounter. As they dig deeper, they discover ties between Rourke and the Grayson family, strange behavior from the Hartfords, and a new deputy whose sudden arrival in Riverview is anything but coincidence.
The cipher leads them into the woods, where a forgotten bunker reveals the truth: Rourke was attacked, forced to flee, and left behind evidence of a dangerous scheme. When Deputy Sloan traps the group underground, the kids must rely on their wits-and Mira's quick thinking-to send a desperate signal for help. The sheriff arrives just in time, and Rourke is found alive, shaken but safe. Grateful for their courage, Rourke rewards each of them with gifts that change their futures.
But Riverview's mysteries are far from over. During restoration of the Grayson Victorian, workers uncover a second hidden compartment-marked with a symbol only Harper recognizes. The danger they faced was just the beginning. The Vanishing Benefactor delivers a gripping blend of small-town atmosphere, high-tech intrigue, and the fierce loyalty of friends who refuse to look away. Perfect for readers who love modern mysteries with classic heart, this fifth installment deepens the Riverview world and sets the stage for the next secret waiting in the shadows.