When 26 year-old Robert Wiles, the promising heir to his family's successful aircraft service company disappears from his Lakeland, Florida office, the FBI have only one clue - a ransom demand from a mysterious "Group X". No witnesses and no forensic evidence surface, forcing investigators to consider that Group X might be a conspiracy within Wiles' company, or Robert Wiles himself.

• Mark Marabella

• Nikolaos Argyros