Where is Indian Island, and why has it been in the news?

Mr. Justice Wargrave reads the political news from the Times as the train rolls through the countryside towards Devon. He recalls all of the recent rumors in the paper regarding Indian Island. According to rumor, an American millionaire had purchased the island and built a luxurious house upon it. The millionaire’s third wife, however, had been a poor sailor, so the house was now up for sale. The gossip columns in the papers each reported different news on the island. Some reported that Miss Gabrielle Turl, a Hollywood film star, bought the place or that it was being purchased as “an abode for Royalty.” The most outlandish gossip was that the Admiralty was buying it in order to carry out “hush hush experiments.”