Jenny Valentine has gone on vacation. While Trouble's away, the Stranger will play. Sunscreen? Check! Phone charger? Packed! Flip-flops? Already wearing them! Trouble? ...Trouble!? Where oh where has our itsy-bitsy spy girl gone? Wasn't it her idea to visit this spooky castle in the Bavarian Alps on the senior class trip in the first place? With Jenny vanished to parts unknown, her classmates find themselves marooned at fearsome Schloss Schwarzwald. The remote fortress-turned-hotel features luxury rooms with gorgeous, scenic views of the mountain range. Don't miss out on the five-star amenities, including: a hedge maze, hiking trails, indoor pool, free WiFi, casino, Michelin Star cooking, ancient curses, hidden treasure, vengeful ghosts, and murder! The Blackbird Springs teens can handle one simple mystery without their Girl Detective, can't they? Or will they find more Danger in Old Bavaria than they bargained for?