The "Mystery Dungeons" you will head for on explorations exist in various regions.  They are like mazes.
There you will encounter various land forms such as caves, bluffs, mountains and forests.
The most profound characteristic of "Mystery Dungeon" is that its layout will change every time you enter it.  So you can go on explorations as many times as you like without getting too familiar with it.
You can find various items and treasures that are useful for explorations in the dungeon.  What and where you'll find them will also change every time you enter.
This means that even if you've already explored a dungeon, you may find some other new treasure the next time.

	Mysterious dungeons with different layouts every time you enter - find the staircase and go further on! Unforeseen hidden treasure may be waiting for you!

Various kinds of Pokémon inhabit different parts of dungeons.
Wild Pokémon may have lost themselves due to one reason or another.  They may attack you upon encounter.
Cooperate with your partner to engage in battles, make your way through and proceed deeper into the dungeons.

	You can meet many new Pokémon that appeared for the first time in "Pokémon Diamond and Pokémon Pearl" such as Chingling, Floatzel, and Purugly. Cooperate with your partner to proceed deeper into the dungeons!

This game will support Nintendo Wi-Fi connection, so if you take fall in a dungeon, you can ask other players from all over to rescue you using Nintendo Wi-Fi connection.  You can also rescue other players in need.