The story follows an unnamed monster-hunter as he ventures into the haunted Tempest Mountain, where reports of inexplicable attacks have left the local inhabitants in a state of fear and terror. As he digs deeper into the mysteries surrounding the foreboding Martense mansion, the hunter uncovers a dark family history that reveals the true nature of the lurking fear that plagues the mountain.

The story begins with the aftermath of a destructive thunderstorm that had devastated the region, leaving behind a trail of destruction that appeared to have been caused by more than just a mere storm. Intrigued by the local legends surrounding the Martense mansion, the hunter, accompanied by his trusty companions, sets out to investigate the eerie happenings. However, their expedition takes a sinister turn when his companions vanish without a trace, and the hunter catches a glimpse of a grotesque monster casting a demonic shadow on the mansion's chimney.

Traumatized by the events in the mansion, the hunter seeks assistance from journalist Arthur Munroe, sharing with him the horrors he has witnessed. Together, they embark on a quest to uncover the truth behind the murderous creature and the Martense family. Sheltering from yet another thunderstorm in an abandoned cabin, the hunter recalls the nightmarish events he endured, only to discover that Munroe has suffered a gruesome fate at the hands of an unseen horror lurking outside.

Undeterred by the horrors he has encountered, the hunter returns to Tempest Mountain, determined to solve the mystery once and for all. He unearths the dark secrets of the Martense family's history and their isolationist tendencies, which led to their intermarriage with the inhabitants of the surrounding area. As the family's bloodline became tainted by centuries of inbreeding, they devolved into hideous ape-like creatures. The ghost of Jan Martense, vengeful and tormented, haunts the mountain and seeks to claim more victims.

In a desperate attempt to put Jan Martense's spirit to rest, the hunter uncovers a subterranean network of tunnels beneath the mansion. As he witnesses the emergence of the grotesque beings from the ground, the horrifying truth materializes before his eyes. The Martense family has deteriorated into monstrous creatures, driven by their insatiable hunger and savage instincts. In an act of self-defense, the hunter shoots one of the creatures, discovering its true identity as a deformed member of the Martense family. Filled with terror and unable to erase the horrors from his mind, the hunter resorts to destroying the mansion and its surroundings, but the lurking fear remains, haunting his every thought.

Lovecraft's ability to weave a suspenseful narrative, punctuated by terrifying imagery and a sense of impending doom, makes this story a must-read for all fans of the horror genre. Brace yourself as you embark on this nightmarish journey into the unknown, where the line between reality and madness becomes frighteningly blurred.