Jessop is the only survivor of the final voyage of the Mortzestus, rescued from drowning by the crew of the passing Sangier. He begins to recount how he came to be aboard the ill-fated Mortzestus, the rumors surrounding the vessel and the unusual events that rapidly increase in both frequency and severity. He describes his confusion and uncertainty about what he believes he has seen, at times fearing for his own sanity.

William Hope Hodgson used his experiences at sea to lend authentic detail to his short horror stories, many of which are set on the ocean. Hodgson was an English author who produced many short stories and novels, spanning several overlapping genres including horror, fantastic fiction, and science fiction.