The Nightsky River
The Nightsky River is, in truth, no river at all. But by toponym, and convention, it is a river nevertheless. The Nightsky is composed of a system of partially flooded caves, mining tunnels and underground ruins that function as an anabranch of the much larger river from which it diverts and rejoins.
According to the old tales, the Nightsky was the product of a magical mishap, some mystical triviality gone awry, causing the earth to collapse and allowing the mighty river to permeate the subterranean world beneath. The tales are vague and confused regarding the nature of the ritual and the identity of those who tried to work it, but it is clear that their invocations have left a lasting impact.
Time flows differently on the Nightsky. Not slower or faster exactly--just, differently. While some of those who enter never leave, whether by dint of choice or circumstance, one feature of the temporal abnormality of the Nightsky is of particular value to sufficiently desperate merchants, travellers and warlords: a successful navigation from one end of the Nightsky to other takes only a single night from the perspective of the world above.
A journey of many days travelling on the river above is reduced to a matter of hours by making it along the Nightsky. At least in the view of those safely on shore. For those traversing the Nightsky, the passage of time within its dim caul is significantly more subjective.
In addition to its status as a miraculous, albeit risky, shortcut the Nightsky contains a variety of outlandish denizens, bizarre treasures and unusual experiences that sometimes attract expeditions by the curious or foolhardy. Entering the Nightsky with the hope of finding anything in particular is, however, an invitation to frustration.
The Nighsky takes its name from the bioluminescent fungus that grows high up on the walls and ceiling of its caves and tunnels, dotting the darkness above with small clusters of light reminiscent of stars in the night sky. Some of those who have traversed the Nightsky for many years even claim that they can navigate by these ersatz stars.
There are no other natural sources of light within the Nightsky, and large stretches of the river may be travelled in near total darkness. However, in many places artificial lights are maintained including torches, oils lamps and even magical light sources. It is said that the lights are maintained by the Lamplighters Guild, and the Guild certainly asserts a claim to extract a toll from travellers on the river, but very few people actually attest to having seen a lamplighter about their work within the Nightsky.
The Nighsky maintains its own microclimate, independent of the weather above. Most of the time the weather is warm and humid, and the air is still. On occasion a chilling wind blows along the course of the river, bringing with it frost and--in extreme cases--icy waters. At times, and much to the surprise of the unprepared, rain falls heavily from the ceiling hihg above.
A variety of animal noises, particularly the chirping of insects and the screeches of bats, echo along the river. It is not uncommon for these sounds to be mixed with other cries, shouts and screams. Underneath everything else is the constant sound of water--dripping from the ceiling above, being stirred by oars and lapping against the walls.
Navigating the Nightsky
There is no foolproof way to navigate the Nightsky. Between journeys, people and places within seem to change positions along the course of the river, apparently without any rhyme or reason. Every journey along the Nightsky is different.
If the player characters are simply seeking to traverse from one end of the Nightsky to the other, roll 1d6+1 times on the Nightsky Encounter Table [note: the full table doesn’t actually exist yet].
If a result is rolled more than once on a single trip, ignore that result but do not re-roll. If the result was a location, make a note of it. The next time the player characters travel on the Nightsky they may choose to reduce the number of encounters rolled by one and visit the noted location during their journey.
If the player characters hire a guide or navigator to take them along the river, they may reroll up to 1d4 results on the Nightsky Encounter Table and choose which result to take. Each encounter may only be re-rolled once.
Unless otherwise noted in an entry on the Nightsky Encounter Table, and regardless of the time that has passed while travelling the Nightsky, only a single night will have passed in the outside world when the player characters emerge.
NIGHTSKY ENCOUNTER TABLE (roll d66)
11 THE LONGEST NIGHT
Roll an additional 2d3 times on the Nightsky Encounter Table. The third time this result is rolled in a single journey, do not roll for any additional encounters, when the player characters emerge from the Nightsky, d66 years will have passed in the outside world.
12 ONCE AND FUTURE
The player characters encounter another vessel on the river. Roll 1d6:
1 - 3 The passengers on the other vessel are the PCs from the future.
4 - 5 The passengers on the other vessel are the PCs from the past
6 The passengers on the other vessel are the PCs from the past, and they are in imminent danger (GMs choice).
If the player characters kill the past version of themselves or allow them to die, the present versions of the player characters die immediately. If the past version of the PCs kill their future selves or are otherwise the survivors of the two groups, feel free to pick up with whatever adventure the past PCs were on.
13 A SHORTCUT TO FUNGUS
The player characters encounter a small island in the middle of the river, overgrown with plants. In the centre of the island there is a five foot tall standing stone carved with weathered runes. On the shore of the island someone has installed a wooden sign reading “Mushrooms”, and a collection of empty wooden buckets lies beneath it.
Engineering minded characters might be able to notice that the island appears to have been artificially created, and that the standing stone sits in its dead centre.
The runes on the standing stone have been worn away with time, and are inscribed in a long forgotten language. If they PCs can use magic or some other clever idea to translate the writing, the runes indicate that the island is a graveyard for traumatic memories.
Any PC who searches the island for mushrooms locates 1d4 rations worth of edible mushrooms. Any PC who speaks out loud the details of a tragic or traumatic memory while searching for mushrooms feels the burden of that memory lifted, and rolls 1d6 on the table below for the unusual mushroom that they find:
1 Portobello of Purging: When introduced into the bloodstream, the affected person experiences intense sadness for 1d6 hours, and will weep uncontrollably during that time. At the end of this period the person experiences a profound sense of tranquility for 1d6 weeks. During that time they are immune to fear and magical effects that produce negative emotions.
2 Warming Agaric: When placed into an enclosed vessel of water, this mushroom slowly disintegrates and causes the water to boil. Anyone who drinks the water is immune from the effects of cold until they next drink something else.
3 Surfactant Sporocarp: A person who immerses themselves in water after eating this mushroom will dissolve into the water and become part of it. This effect lasts for 3d6 hours, after which time the person coalesces into their solid form.
4 Sympathetic Milk-cap: When this mushroom is cut or bruised, it exudes a white milk that can be applied to wounds to heal them [1d8 HP]. When the mushroom is damaged, the person who last touched it to their bare skin suffers a powerful pain as if they themselves had been cut or struck; however, no lasting physical damage is caused. After extracting milk from the mushroom roll 1d4, on a result of 1 the mushroom is destroyed.
5 Memetic Morel: When used in cooking, the cook can impart a sense-memory into the mushroom. Anybody who subsequently consumes a dish that contains the mushroom will vividly experience the sense memory.
6 Ilitog’s Death Cap: When this mushroom is consumed, if the person who ate it has given up on life or lost the will to live, their heart stops immediately and they die peacefully within seconds.