The treasure of the prophet Muhammad is held in the holy city of Mecca. Patra Lawrence, daughter of Lawrence of Arabia, is guarding it as head of mosque. 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. 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 him on the other side.