Plot Summary:Sherlock Holmes is approached by Mrs. Adelaide Savage who is concerned about her husband, Victor. He is a successful and rich financier by profession but is a poet at heart. He has taken to using opium regularly and has been acting strangely, she believes, as a result. Holmes accepts to look into the case and soon spends a weekend at their country estate. There he finds that Culverton Smith, Savage's cousin, is also in residence. A bookish man, whose only accomplishment is to be known as the principal authority on a very rare tropical poison, Smith's behavior is odd from the outset. Savage is clearly a sick man and when he dies, Holmes surprises Watson - who is certain Smith responsible - by seeming somewhat nonchalant about it all. When Holmes himself becomes deathly ill, apparently with the same affliction that struck Savage, he summons him to Baker Street to close the case.