A year ago, the Aiye siblings lost their parents and sister in a mysterious train accident. But when the eerie Ms. Crowe shows up on their doorstep, she reveals that it wasn't an accident at all.

With their sleepy Great Aunt Victoria reluctantly along for the ride, the kids are plunged into a world of puzzles, secret codes, and hidden dangers. Their father, a famous inventor, left behind his greatest creation-a puzzle only they can solve. But as they dive deeper into the mystery, they start to wonder: who can they really trust?