This generally readable & fast paced action story is the third in a series by Niven about the first Martian explorations. This is not an independent story; it assumes you have read the previous one - "How the Heroes Die"; there are parts that assume you have read the first story in the series too - "Eye of an Octopus".
Story summary.This is a frame story - main story is narrated by Muller into his ship's log (entries dated 20-30 April, 2112). The record is shown by Lit Shaeffer, an official of the colonies of (the asteroid) Belt, to 170 year old Lucas Garner, an earth official visiting them. Two Belt ships had visited Mars - nominally an earth colony - without permission from earth; Lit wants to pre-empt any possible misunderstandings.
The frame also contains a lot of unrelated stuff. I will just ignore it, & go to main story.
Muller is a native of the Belt, & a smuggler. He has picked up supposedly valuable "twenty kilos of pure north magnetic poles" & is headed towards moon ("Luna") in his private ship, & this activity is considered illegal by the Belt government. Government vessel is chasing him.
To escape his persuers, Muller decides to land on Mars (or is forced to land by a sharp turn around it - I don't recollect). His ship is not equiped to land on an airy planet with heavy gravity - ends up with his "fuel tanks tearing loose" on the way down; but there is some fuel still in "inboard cooling tank". Lands near "Lacis Solis base" aka "bubbletown" - the site of human camp in previous story "How the Heroes Die" - with a damaged ship; but damage is not so bad he cannot take off.
Title comes from this landing. To a Belter used to low or no gravity, going down towards high gravity planatary surface is like going into a (gravity) hole.
This is where he will discover the fate of previous expedition 70 years ago - all dead - and will meet his own death. But he will discover the cause - so future explorers will be prepared.
He finds 12 dead bodies inside "bubbletown". Of the original 15 explorers, 3 had died in "How the Heroes Die" of mutual fighting. Remaining seem to have died unprepared in a blowout - air leaks created in the bubbletown walls. We will later learn that the leaks were an act of sabotage on the part of Martian natives.
It left me puzzled how no one on earth bothered about the fate of this earlier expedition for 70 years! They were supposed to have been picked up by an earth ship. This story hints earth was not even aware they had died!
During his early exploration of surroundings, we also learn something about the Martian surface not told in previous stories in so much detail (at least I don't recall) - the surface has a very thick layer of dry very fine dust powder that almost behaves like it were fluid - much like moon dust in Arthur Clarke's "A Fall of Moondust".
It is in this thick layer of fine dust that sentient Martians burrow & live! This is also given as the reason previous two expeditions & satellite scans did not discover the location of Martian cities - which obviously must have existed, because of evidence of advanced local technology.
We will also learn the purpose of "wells" - this was the close to the theme of the first story in the series, "Eye of an Octopus". The wells are crematoria. Since there is no fire on Mars, they dumped their dead in the well of water. We were told in the first story that native biochemistry is such that they explode on contact with water - so crematorium does an effective job. I could not figure out, in the light of this, why some Martians were actually buried near well (first story found a well preserved mummy).
Anyway, after some hard work, Muller succeeds in fixing the many leaks of bubbletown, gets the oxygen generator working by connecting it to his ship's power source, distills water, & inflates bubbletown.
When he is ready for take off, he discovers he cannot lift. Cannot even troubleshoot, since the ship is buried deep in sand - turned to glass by high temperatures when he landed. We are given an argument I don't quite recollect - to the effect that Martians are short of power sources, & stole his; this apparently was also the reason for previous attack on bubbletown.
End will see an attack by "spear" wielding Martians (we are not told what the spears are made off). Bubbletown is punctured & he is doomed. But before going down, he manages to throw water at some of the attackers - killing 6.
A Belt ship tracking him will later collect him, dead Martians, & their spears.
- Arthur Clarke's "A Fall of Moondust": Key plot elements of this novel depend on deep seas of dust so fine it behaves like a fluid; it also hides anything buried underneath from sky surveillance. Similar dust is found on Mars in this Niven story that has also hidden native Martian cities from satellite human surveillance; only Niven also gives an argument why such dust cannot exist on moon!
Fact sheet."At the Bottom of a Hole", short story, review
First published: Galaxy Science Fiction, December 1966.
Series: "Eye of an Octopus" (B), "How the Heroes Die" (A), "At the Bottom of a Hole".