The Shadow Over Innsmouth (Fantasy and Horror Classics‪)‬

You can escape the town, but you can't escape your bloodline.

A young man named Robert Olmstead, embarking on a sightseeing tour of New England, decides to visit the isolated, decaying coastal town of Innsmouth, Massachusetts. The town is notorious throughout the region for its dilapidated state, strange history, and the grotesque, peculiar appearance of its inbred inhabitants, often called the "Innsmouth look."

Olmstead's initial morbid curiosity quickly transforms into profound dread as he encounters the town's secretive, shuffling residents, who possess bulging, unblinking eyes, flat noses, and strangely wrinkled skin. He soon learns of the town's terrifying history: decades ago, a local sea captain named Obed Marsh made an unspeakable pact with the Deep Ones, a race of immortal, amphibious humanoids who dwell in the deep ocean.

The pact involved sacrificing humans to the Deep Ones in exchange for gold and boundless fishing. Crucially, it also involved the grotesque "interbreeding" of the species. The inhabitants of Innsmouth are slowly transforming into the hideous Deep Ones, and upon reaching a certain age, they descend into the ocean to live eternally in the colossal, sunken city of Y'ha-nthlei.

Trapped in a rundown hotel, Olmstead narrowly escapes a terrifying nighttime chase by the transforming townspeople. His escape is ultimately rendered meaningless when he discovers a devastating secret about his own lineage. Through genealogical research, he finds that his own great-grandmother was a member of the Marsh family, meaning the "Innsmouth look" and the inevitable transformation awaits him as well.

The Shadow Over Innsmouth is a definitive, core novella of the Cthulhu Mythos and one of H. P. Lovecraft's most chilling tales of hereditary and biological horror. It is a profound exploration of identity, degeneration, and the terrifying idea that one's own body and ancestry are an inescapable source of cosmic dread.