After dealing with the Shut in the Balkans, Kara Ben-Nemsi ('Karl the German') receives a firman (precious passport) from the padishah (Ottoman sultan) before he continues his travels through Kurdistan. Achmed El Corda, the son of Halef's Hadedhin Beduin tribe's sheik Mohammed Emin, has been captured by the machredsh (Turkish governor) of Mossul for resisting water seizure by his Turkish troops. Kara takes charge of the rescue.
Dr. Mabuse has been locked away for years in an insane asylum. Suddenly crimes start occurring and no one knows the culprit. A detective goes to visit the Doctor to find some sort of clues to the robberies.
Kara Ben-Nemsi, friends and rescuers set out to free a young relative of the guardian of the treasure of the Chaldaeans (Christian sect), who is captured for that fabulous ransom.
