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.

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%).