A Plot refers to the land you are given at the start of the game in which to create your prison on.
At the beginning, they come in three sizes:
You also have the choice to add just one or all of these extras:
- Generate Forests
- Generate Lakes
- Generate Buildings
You can cut the wood down from the forests and sell it and you can't build on lakes so it limits land a bit. However, when you pick to generate buildings, these can be used to come up with a design or removed.