Pella, 334 B.C. In the capital of ancient Macedonia, Alexander the Great is organizing a grand celebration before the start of his campaign against the Persians. Two twelve-year-old friends, Cassander and Phrixus, secretly descend into the palace's underground chambers. When Cassander enters the royal cellar, he accidentally overhears conversations. He hides and sees two men talking quietly and suspiciously. After they leave, Cassander discovers a half-burned message that they unsuccessfully tried to destroy in the room's fireplace. He finds his friend and they seek help from Thessalonike, Alexander the Great's younger sister. The three friends will soon find themselves in the midst of a great conspiracy centered around the palace itself, unaware that others are already watching them...

Will the great campaign into the depths of Asia be saved?