Sally Lockhart was only sixteen years old when her father died under mysterious circumstances, leaving her alone to face a dark secret whose solution determined her life. After uncovering the mystery of the Maharajah's ruby, Sally changed her destiny and found new friends. However, several years later, the courageous girl and her friends must once again become detectives. The random events that befell each of them turn out to be links in a single chain. And behind it all stands the all-powerful owner of the Polar Star company and creator of a deadly weapon. With every step, Sally, Jim, and Fred are drawn deeper into the sinister shadow of Polar Star.