The treasure of the prophet Mahomet is held in the Islam holy city of Mecca. Patra Lawrence, daughter of Lawrence of Arabia, is guarding it as head of mosque security, because if she does, she will be accepted as a Moslem. It's secured in a vault operated by crude oil pressure. So long as the crude oil pressure does not drop, the vault cannot be opened. Fujiko is nowhere to be seen, but when Lupin concludes from the arrangement of the Earth's tectonic plates that drilling a new well at the South Pole should do the trick, he finds a trap awaiting his swift attack.