From the introduction:
For this adventure a group of younger but promising members of the Odyssians are invited out for a weekend at the country estate of Sir Henry Ainsford, one of the older members of the club. Sir Henry is noted as a hunter and explorer, but he is getting on in years and spends most of his time at his estate outside of the town of Ashburn in Kent.
Sir Henry regularly invites Odyssians out for weekend visits, but this particular weekend is special, because he believes he has made a discovery of great scientific importance on the grounds of his estate. This means that he will make sure that Odyssians of particular interests will be in his group. He will invite archaeologists, paleontologists, physicians, historians and ethnologists in particular, plus an assortment of others who are interested. He will also invite his two oldest friends in the Odyssians, Professor Milton Morrisson of the Language and Ethnology faculty at Oxford and Admiral Sir Joseph Porter (retired). All he tells anyone in advance is that he has made a discovery which may revolutionize the history and science of human origins.