Pokémon Mystery Dungeon: Blue Rescue Team and Red Rescue Team/Mt. Faraway

Grab a key and get in once you have beaten all three fields. It's time to find the Mirage Pokémon. But before you do, you've got to face the final test: Mt. Faraway.

The Dungeon
On the 30th floor, you'll find a locked door. Use the Key to get the Friend Bow.

Also you must have completed Fiery Field, Lighting Field and Northwind Field to gain access.

Items
A rare item you can find in here you can't find anywhere else is the Friend Bow. You find it on the B30F in a locked vault, so you need a key to open it. The Friend Bow is a great item, increasing the chances of a Pokémon joining your team.

Enemies
You'll find an array of Pokémon here. The ones you don't need to worry about are the on around floors 1-20. After level 20 things start getting more difficult.

Boss Battle: Ho-Oh
Finally, the summit. The mirage Pokémon appears. You never suspected it. The High King Ho-Oh. He's not easy (after all, he is the High King). After beating him, return with the friend area Rainbow Peak and defeat him again (he has a recruitment chance of 99.9%).