From Bulbapedia, the community-driven Pokémon encyclopedia.
Scorched Plains (Japanese: やけのはら Burnt Field) is a Friend Area in Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team. It can be bought for 5,000 Poké from Wigglytuff in Pokémon Square, or can be unlocked if the player receives Cyndaquil or Torchic as their starter or partner. It is in the Volcano area, and has a capacity of ten Pokémon. All the Pokémon here are at least partially Fire-type.
It is a Volcanic area, with a large open area in the center, with are flaming rocks surrounding it. The overall shape is very similar to the Friend Area Wild Plains.
The tremendously hot ground of this grassy field of fire spouts flames. It is a treasure trove of Fire-type Pokémon.