S02E03 - The Lost Mine

Poirot and Hastings are discussing investments and Poirot informs Hastings that he has no thing of that kind except for fourteen thousand shares in Burma Mines Ltd which were given to him as a gift for services rendered. He offers to tell the story of what service he provided and Hastings gladly listens...
The mines in question were originally silver mines, discovered by the Chinese in the fifteenth century. The silver was all worked out but plenty of lead remained, not considered being of value at the time but definitely worthy of exploitation at the time of the story. The mine itself was lost, the only clue to its location being old papers in the hands of a Chinese family. The head of the family, Wu Ling, agreed to negotiate a sale of the papers and travelled to England to complete the transaction. Wu Ling was supposed to be met by one of the syndicate company directors, Mr. Pearson, in Southampton but his train there was delayed with the result that Wu Ling made his own way to London where he booked into the Hotel Russell Square and telephoned the company to say that he would see them the next day. He failed to appear at the meeting and the hotel was contacted. They said Wu Ling had gone out earlier with a friend. He still failed to appear at the offices throughout the day. The police were contacted and the next evening the Chinaman's body was found floating in the Thames.