The Call of Cthulhu

In the story, a dying professor leaves his great-nephew a collection of documents pertaining to the Cthulhu Cult. The nephew begins to learn why the study of the cult so fascinated his grandfather. Bit-by-bit he begins piecing together the dread implications of his grandfather's inquiries, and soon he takes on investigating the Cthulhu cult as a crusade of his own. As he pieces together the dreadful and disturbing reality of the situation, his own sanity begins to crumble. In the end, he passes the torch to his psychiatrist, who in turn hears Cthulhu's call.