->''Adventure isn't dead. It's just gone to Hell.''

[[quoteright:200:https://static.tvtropes.org/pmwiki/pub/images/The_Descent_by_Jeff_Long_book_cover_1845.jpg]]
[[caption-width-right:200:[[WhatIf What if Hell was an actual place on Earth?]]]]

''The Descent'' is a 1999 science-fiction/horror novel by American author Jeff Long focusing on the discovery and exploration of [[BeneathTheEarth an extensive labyrinth of tunnels and passages stretching throughout the sub-surface of the entire world]], inhabited by several species of alternately-evolved troglobitic hominids who have adapted to their underground condition. While [[AlwaysChaoticEvil presently degenerate and brutal]], the "hadals" had once possessed a high level of civilization, having reached the Iron Age as far back as 20,000 years ago and [[BenevolentPrecursors mentored subsequent human civilizations]]. [[DoingInTheWizard Their fall from grace formed the basis of the historical belief in demons]].

The book is split between two storylines. The first concerns an ill-fated expedition into the sub-planet. The other about the Beowulf Club, [[BadassBookworm a group of highly-determined scholars]] who set out to find the historical figure who inspired the legends of TheDevil. Eventually, these two stories intersect as the expedition comes face-to-face with Satan himself.

Has nothing to do with the video game series ''VideoGame/{{Descent}}''. Nor the 2005 British horror film ''[[Film/TheDescent The Descent]]'' written and directed by Neil Marshall, although there are certainly similarities. The novel was followed by a sequel, ''Deeper.''
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!!''Literature/TheDescent'' contains examples of:

* AlwaysChaoticEvil: Reconstructed. Lip service is paid to the idea that the hadals simply act out of a culture with [[BlueAndOrangeMorality a different set of expectations about good and evil]]. None of that changes the fact that hadal behavior towards outsiders involves hefty doses of what humans would consider [[MoralEventHorizon slavery, rape, mutilation, torture and cannibalism]].
* ApocalypseHow: [[spoiler:At the end, the hadals are decimated by a man-made plague. ''Deeper'' also finishes with the very strong implication that China and the United States have started a nuclear war.]]
* BeneathTheEarth: The discovery and exploration of the sub-planet drives the plot of the novel.
* BetterToDieThanBeKilled: Considering that hadal captivity often leads to cannibalism and trauma-induced psychosis among humans, many characters choose to commit suicide instead.
* BreedingSlave: Generally what happens to women captured by the hadals.
* ColdBloodedTorture: Humans captured by hadals are subject to an "initiation" that essentially amounts to this, involving beatings, crude forced tattooing, and ritual mutilation.
* CruelAndUnusualDeath: ''Rampant'', and generally inflicted by the hadals. Some of the mercenaries they capture are gutted and tied to pillars with their own entrails, after which their eyes are torn out and replaced with pebbles and their lower jaws ripped off. They're ''still alive'' at this stage, although they mercifully die eventually.
* DoingInTheWizard: The novel goes to great lengths to show that seemingly supernatural phenomena observed in the sub-planet are rooted in science. WeirdScience, but science nonetheless. Subverted in ''Deeper'' when [[spoiler:Satan turns out to be a real, immortal entity whose existence has no explanation behind it]].
* GodEmperor: The hadal view of "Satan." [[spoiler:Their "Satan" is actually a proxy of the ''real'' one. Whether the hadals know this is unclear.]]
* HumanResources: An artifacts exhibit shows hadal weapons made of human bones. The hadals also make clothing and other objects out of human leather, and sometimes use their human slaves as a food source.
* HumanSubspecies: The hadals, a.k.a. ''Homo hadalis'', a human species that lives BeneathTheEarth in the caverns of the sub-planet. Descended from ''Homo erectus'', they once had a relatively advanced Iron Age civilization millennia before humans did, but they have since degenerated into [[TheMorlocks vicious underground savages]] with a penchant for abducting people as slaves and food.
* HumanoidAbomination: The hadals are just another species of human, but the Angel[[spoiler:/Satan/Older-than-old]] is ''definitely'' something of this nature.
* ImAHumanitarian: One of the defining characteristics of ''Homo hadalis''. {{Justified|Trope}} by the fact that they live underground, where there are no plants and no animals bigger than the hadals themselves. People are the ''only'' big animals readily available for hadals to eat.
* InvasionOfTheBabySnatchers: About a quarter of the way through ''Deeper'', the hadals kidnap dozens of young children across the United States on Halloween night. They brutally kill anyone who tries to stop them; this amounts to about a hundred people, mostly parents who tried to defend their children, although they also murder the entire staff of a haunted house. Perhaps the most effective portrayal of the incident's horror is a police log from Tucson, which starts off normal but rapidly racks up murders and child abductions one after another until the Amber Alert system ''crashes''.
* MadeASlave: The fate of the hadals' captives, with protracted torture to boot.
* TheMorlocks: The pale cave-dwelling cannibal hadals fit this trope.
* OurDemonsAreDifferent: First off, they are not demons. They are cave-dwelling hominids with [[AlwaysChaoticEvil a culture that makes the Aztecs look like the Amish]]. Also, they are revealed to be able to [[spoiler:transmit the consciousness of their dead into other sapient lifeforms via electrical currents]].
* PetTheDog: Given their [[FateWorseThanDeath nigh-unimaginable]] treatment of adult captives, the hadals treat captured children surprisingly well. They feed and care for them as best they can, and go out of their way to keep them safe from harm and abuse. It's implied that the hadals' own birth rates have been declining for centuries, and surface-born children are taken to round out their own depleted numbers.
* PhysicalHell: It turns out that there's an underground world under ours, inhabited by cruel demon-like humanoids. There's also a {{Satan}}... of sorts.
* {{Satan}}: The members of the Beowulf Club infer by ''a priori'' reasoning (i.e., guessing) that if the sub-planet and hadals have been the inspiration for hell and demons, the figure of Satan in mythology must also be based on a real person who has been reincarnating over the ages. [[spoiler:They're right, and he's one among their own number.]]
* ShoutOut: Where to begin?
** The expedition into the sub-planet is called [[Literature/JourneyToTheCenterOfTheEarth the Jules Vernes Society]].
** The group of scholars looking for {{Satan}} are called [[Literature/{{Beowulf}} the Beowulf Club]].
** An entrance into the sub-planet inspired Dante in [[Literature/TheDivineComedy his depiction of Hell]].
* UsefulNotes/StockholmSyndrome: Captives of the hadals often end up emotionally dependent on them after years of abuse. Even after being rescued, many have a hard time overcoming their feelings of attachment.
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