Need Campaign Design Help

[Dannyalcatraz]

The Green: a demiplane the size of a gas giant that consists of a single great tree that has grown in all directions, filling it with a latticework of wood and leaves. Gravity's direction is towards the center, where the tree roots in an earth-sized ball of sand, muck and stone covered by a mile-deep brackish sea. The climate is like that of a rain forest, so the atmosphere is humid, there is always a mist, drizzle, rain or even just beads of condensation.

Just like in a typical rainforest, though, there are other plants, most of which get their water directly from the atmosphere. Some, though, get their water from their prey. There is at least one race of sentient plants.

Intelligent animal inhabitants are varied, but mammals, avians, arthropods and arboreal amphibians predominate. Standard PC races like elves, gnomes, goblins and the like have evolved for an arboreal life, having either evolved or using magic to develop gliding membranes, wings, or gripping feet.

Most civilizations are about stone age in tech level, with fire-hardened wood or bark harvested from the One Tree substituting for stone.

The ecosystem has been fairly stable for tens of thousands of years...but now, there comes the Blight. Nobody knows its origins, but it is some kind of magic-resistant fungus that affects both flora and fauna. Many suspect it is not native to The Green. Some suspect it is not even natural.

 

[fafhrd]

I'm glad you guys like the Stepstones.
If you're looking for ideas that aren't quite so inimical...

Drydock:

It is a little known truth that spelljamming craft were originally developed not in the pursuit of knowledge or conquest, but rather, in search of new markets, by that most pecuniary of species, the Mercane. Being cautious of nature, the Mercane designed a failsafe into each spelljamming helm that allows the craft to plane shift to a special destination when the helm is otherwise disabled. That destination is the demiplane known as Drydock. Though spelljamming dweomercraft has passed through many hands, this simple instruction has often been retained in schematics.

Drydock is a sphere whose interior surface is covered with gantries and spires as well as other more common structures. The center of the mile wide plane is occupied by a large apparatus with the appearance of an armillary sphere containing a small blue sun. While providing the plane's diffuse blue light, the sphere primarily serves as the beacon that allows for spelljamming helms to return when unable to complete other shifts.

New arrivals are greeted by teams on skiffs and then led to a berth where repairs can be negotiated. Of course, the mercane also offer a wide variety of wares, services and lodging on the shell.

Those unfortunates who lack both serviceable craft and funds for repair end up either marooned on tangles of derelict craft or working for the mercane. The most dangerous of the employed serve as Drydock security forces.

Essentially, it's a chance for PCs to unload some items, spend their gold, and possibly get involved in a little intrigue. There are plenty of creatures eager to leave, and mercane justice shields only the mercane.