Preliminary - The Gardens of Ynn

I've gotten inspired and I'm writing up a module. Players explore a procedurally-generated ruined extradimensional garden. 

Here's the basics of it, before I come up with the various random tables and entries.

Into the Gardens of Ynn

A module for old-school roleplaying games.

What are the Gardens of Ynn?

Ynn is a perpendicular world. Compare the concept of parallel worlds: from any place in the real world, you can cross over to an equivallent in the parallel world. Any place has it’s parallel version, just shifted slightly. A perpendicular world, meanwhile, exists at right-angles to reality. Crossing over at a certain point, the further one travels into the perpendicular world, the less like reality it becomes.

Of the dazzling variety of such worlds, Ynn is just one. It appears as a vast garden, now untended, overrun, and fallen into ruin. Once, this place was a realm of rarefied luxury, but its masters are long dead and the machinery that maintained it has fallen into disrepair.

How Do You Get to The Gardens of Ynn?

The process is simple to those in the know.

In any garden in any place* find a wall covered in ivy, vines, moss, or similar. Clear that vegetation away, and using chalk and charcoal draw a realistic door (with keyhole, hinges and doorknob) on the surface below. Write upon the door
“Ynn, by way of [the current location]”.

 Leave, so the drawing is no longer visible, and on return the drawing will be replaced by a real door. When it is opened, the Gardens of Ynn will be on the other side. The doorway remains there for a full day, after which it fades away as if it never existed, leaving anybody still on the other side stranded.

*any place where there is a garden. In other worlds, if there are gardens, one can access Ynn. One could even escape Hell this way, if one could find a garden there.

How Do the Players Know This?

Roll on the table below. The source of their information only mentions a specific wall in a specific garden, but any one will do.

1. An old gardener tells them in a pub. One of his friends went through by mistake, and when he came back he was stark staring mad.
2. Somebody slips a pamphlet ('Ye Fabulouse Gardyn') into their pocket. It's proscribed by the state as the work of witches, but what if it works?
3. They find an old book ('Journeys in Ynn') in the marketplace. It is written by an old esotericist, detailing their journeys. The text is old and hard to translate.
4. Everybody in town is gossiping about Mad Hettie, who drew a doorway, went through to the world of the fairies, and never came back.
5. A PC inherits the possessions of a dead reletive; a small cottage in the countryside. In the pretty little garden, there is a suitable wall. On the bedside tables, there are instructions on how to get to 'The Other Garden' and a dire warning never to do so.
6. The city guard chased Black Alloicius, the wizard-thief, into the local park, where everybody saw him draw a doorway and then run through it. There's a bounty if you go through after him and bring him back.

How to Run the Adventure.

When the players first step through to Ynn, roll a d20 on table XX (locations) to see where their doorway leads. In addition, roll a d20 on table XX (details) for the specifics of the place, and on table XX (events) for anything that’s going on there. Name the place by rolling 3 d20s on table XX.

You will map out Ynn every time the players visit it.

Take a sheet of paper. In the centre, at the top, write in the location where the players entered. This is layer 0. Here, the players have 3 options. These are:

• Stay Here
• Go Deeper
• Go Back.

When the player’s Stay Here, they remain in the same location. Every turn after the first, roll for Events.

Whenever the players Go Deeper, draw a line from their current location, leading down and write the location they find at the end.

Roll on table XX for the location; a d20 plus the layer they are now on. So, the first time they Go Deeper that takes them down to layer 1, so roll d20+1. If they go down again from there, that’s layer 2, so d20+2.

From a given location, the players can Go Deeper multiple times. Each time they do, draw a new line from the current location, branching off.

When the players Go Back, they travel back up the line, to the previous location on the previous layer. They can Stay Here there, Go Back Again, or Go Deeper again, either to a location they visited before or to a new location (roll it up).

So you end up with a pyramid of branching paths leading down to new areas. The more players explore, the more they open up.
Deeper layers are more dangerous; the further down the tables you go, the weirder and nastier stuff gets. Then again, the treasure down there is better, too.

Every time players visit the Gardens of Ynn, roll up a new starting location from scratch.