Arthur "Bash Man" is the school thug, paid with candy to bully and threaten other students. When genius orphan Darius Drake employs Arthur to help him discover the origin of a suspicious threat, written in blood, they uncover a mystery that involves Darius's estranged grandfather, who was imprisoned for forging evidence in a search for a long-lost diamond necklace worth millions. The boys make the dangerous decision to search for the jewels themselves -- and in the process, they discover that the car crash that killed Darius's parents was not an accident at all. Who will be next?