Robert McFarlane's “Underland:" a review in 1d12 plot hooks

Robert McFarlane's “Underland: A Deep Time Journey" is about the IRL underdark in its various manifestations. If you don't play D&D, this isn't frankly a very meaningful heading - what do the Paris catacombs, Slovenian karstland, and nuclear waste fillage sites have in common other than being sources of danger beneath the surface? It ends up being a mix of environmentalism, Boy's Own adventure (setting up tents in the katabatic winds, &c.) and a genre journalists love but I normally hate, "talking about a science subject but interlarded with impressionistic details about the scientists the author talked to." But if you do play D&D (which you do, because you're reading this blog) and do like occasionally purple prose (which you do, because you're reading this blog) then you might find it's to your liking. Even the otherwise unendurable "scientists I have interviewed" sections are easily borne for their lexicographical lushness; and MacFarlane has a special affection for words that convey geographical specificity: words I highlit for definitions in my Kindle copy include caliche, calve, gaff, windslab, firn, frazil, chamois, leach, corrie, coulois, fulmar, turlough, moulin, marram, slew, pleach, bleb, potash, ruche, stile, kist. These landscapes and underground spaces are liable to inspire MacFarlane to righteousness and/or sentimentality, which can either carry or sink the energy of the writing, depending on the varying levels of self-consciousness and affectation with which he treats them. 

Anyway, here is a summary by way of loosely inspired, and/or cravenly looted, plot hooks.

1. There is not buried treasure in this cave, but a buried person - very recently buried, not even dead yet, a fellow explorer caught in a crevice. With each exhale they slip further into their crevice, and with each inhale they deplete the oxygen in their chamber. You must find them on a clock, and the equipment that could otherwise get them out will not itself survive the narrow passages and waters through which you will have to swim to get there.
2. Thousands of generations have used the ground here for burial, such that one can hardly furrow the soil but in doing so spew up some buried treasure, or inspire a long-interred ghost to jealousy. The people here must practice their growing in raised beds, and send their own dead off to sea, or to relatives in foreign lands, so as not to disturb the previous inhabitants and their wares; though there are heedless men who come in to practice just such disruption, sailing home with haunted gold.
3. Deep beneath the earth a technomagically advanced civilization has built a magical observation post. They are listening for the whispers of dead gods, or the voice of the sun, or the the songs of the stars. These things carry through the matter of the world, but it is only deep beneath the earth, where so few things live and cast magic, that their faint traces can be heard against the aura noise of the surface ecosystem and its civilizations. (Is this what Deep Carbon observatory is about? Don't spoil me; I haven't read or played it yet.)
4. Trees observe all things, but in the slowness of deep time. Mycorhizzal networks send nutrients and information between the roots of trees and hyphae of fungi, which bloom fruiting bodies which the cunning folk fo the forest consume as entheogens. The magic mushrooms are not messages from anthropomorphic gods but from the very physical and superficially ordinary citizens of the forest, the trees. The hallucinations are a dip into the experience of tree-time and tree-priorities, into the chatty crowd of the myrorrhizal networks itself, and may contain direct instructions as to how the Will of the Forest may be manifest. This may be a wise instruction of environmental preservation, or it may be an instruction to clear and destroy another forest that this one has been at war with for hundreds of years, or things stranger to human priorities.
5. Beneath this city is a catacomb, a flipsided double of the city in which is buried all its history, and many great buried treasures. Though the government of the city proscribes entrance, there is nevertheless a subculture of delvers, danger-indifferent nutcases who congregate in their own special bars between descending into the underground twin. So far, so familiar, right? But this culture has its own rules, its own strictures to prevent the instrusion of the above-ground market society from invading its underland cityscape. They barter and exchange gifts, never buy or sell for money, and one does not deface or otherwise loot the history of the undercity, which must be preserved into eternity. They explore, they keep and exchange secret maps, they drink wine and take drugs in underground abandoned operahouses and salons which one must defy death to reach. Prestige amongst each other is the only reward.
6. In this karstland, rivers dip underground and then surface again, then dip below again, like playing dolphins. Men daub pinecones in ochre, place them on a stream, see where they emerge. A generation ago they started started surfacing with little ribbons tied around them, messages in Aklo or Undercommon, and so men wrote messagesin the common tongue when they sent them down. A pidgin has developed between two people who have never gazed upon each others' faces, one of whom has never gazed on the sun.
7. A war was fought in this karstland. Weapon caches can still be found in the hollows of mountains. In deep natural pits, the terror-knights and more dubiously guilty conscripts of the Dark Lord were tossed by the heroes of our grandmothers' generation, a literally grave form of execution, and adherents of the Dark Lord gather in caves, at these pits, to honor their own martyrs, to hear the whispers of their gosts, and to swear oaths of revenge.
8. The treasure of these parts is to be found in the cave-paintings. They function as spell-scrolls, but are so specific to their particular location - the bulge of this man's member matching the bulge on the wall, the slope of the wall suggesting the curvature of the hill that antelope are being driven down into - that they cannot be moved, only studied once before being cast, and then delving in again to study again. (Emmy Allen's Wolf-Packs and Winter Snow already does this, so I don't know if this counts as inspired by "Underland," but I was at least reminded of it, which counts enough for me.)
9. There was a village on this small frosty island, once, but some generations ago the government decided it was too harsh to live there - or had some more ulterior reason for leaving it uninhabited - and resettled them somewhere more normal. Now you have some reason to adventure there, but the only people with the folk-knowledge of how to deal with its unique geography and challenges are elderly women and men, operating off their memories from childhood.
10. The creaking and clicking of this glacier is monitored by the local scientist-shamans, who have developed special divinatory procedures and omen tables for translating the shotgun sounds of its calving slowing into ocean. The glacier has a personality and does not care about human values or human time, and it can tend towards something easily anthropomorphized as cruelty. Thankfully its priests are on the side of the human community around it, and there to appease, negotiate, and craft win-win deals with it - mostly. Sometimes they lose contact with the human community and come to be more familiar with the click-click-crash-boom-click talk of the icy god, are more allied with it than their brothers and sisters.
11. More spell scrolls. Ten thousand years ago the elf-kingdom which stood in this frozen waste, from their floating castles of ice in the clouds, wove songs as spells, and the sound of those spells mingled with the fresh-fallen firn atop the glaciers. Further snow fell on that, trapping the air in pockets, compressing it down to solid ice, and over the centuries and millennia to an impossibly pressurized substance where the song-air is still trapped in flattened, whorled pockets, waiting to be completed. A brave, blasphemous adventurer can abseil down a moulin, carve out the blue substance of the bottom, and unleash the spell - but beware, for to decode what it is would take twelve hours, and for it to melt and be unleashed only takes one.
12. Those who, so long ago, buried these dangerous artifacts considered (and maybe even built) a "this is not a place of honor"-style warning tomb for them. But that was only one line of defense, one not suited for culturally adapting the warnings to future generations and even species. An "atomic preisthood" was founded, whose mysteries were the truth and whose myths would be adapted down on forever, forever warning people against delving into the Forbidden Zone. These myths have radiated and become all the impossibly confused rites and religions and folklore of the present world.