Oil-rich sheikh funds Morris, a wimpish psycholinguist, to continue researches into the language abilities of Morris"s chimp, Dinah, in his desert palace. The local marsh-people, not Arabs, have a uniquely complex language, which Morris is studying. By custom they provide the sheikh"s personal bodyguard. There is oil under the marshes, but its exploitation would break an ancient treaty with the marsh people. The sheikh is murdered, apparently by his bodyguard. Dinah is the only witness. Morris goes into the marshes to discover the truth.