The Distortion World
One of new areas to explore in Pokémon Platinum is The Distortion World. This is where you'll find Giratina in the game; that is, after you get through the confusing array of platforms and obstacles littered throughout The Distortion World. After the events that occur with Cyrus a-top the Spear Pillar, you and Cynthia will chase after Cyrus and Giratina in The Distortion World.
Once inside, you'll find a confusing array of platforms, rocks, and tiles all around. There are no items or wild Pokémon here. Talk with Cynthia and head down the platforms that move when you step on a tile. The platforms will move in various directions, but in a linear fashion at first. Just continue down. Along the way, you'll see Cyrus and Giratina on your way to the bottom.
Some platforms appear perpendicular, and the screen will change views. The controls are the same; just a little awkward. Look for a tile where you get off to resume the normal view.
Eventually after continuing downwards, and jumping on tiles that seemly appear out of no where, you'll come across a puzzle to solve with Mesprit, Azelf, and Uxie (in that order). Basically, you need to push the boulders down into the hole where the Pokémon hovers above. The hardest part can be just getting to the boulders. You'll have to do a little backtracking up and around to reach them. You'll pass through a disappearing forest and even ride a waterfall upside down to reach two of the three boulders.
After pushing all three boulders, talk to Cynthia and a platform will take you down to Cyrus and Giratina. You'll then battle Cyrus:
Cyrus and Giratina
| Cyrus's Pokémon: |  Houndoom level 45 |
 Crobat level 46 |
 Gyarados level 46 |
 Honchkrow level 47 |
 Weavile level 48 |
|---|
Next up, Giratina:
| Giratina |
 level 47 Ghost/Dragon |
Turnback Cave and the Griseous Orb
Upon leaving the Distortion World, you'll notice that Giratina will change into it's Altered forme (from Diamond/Pearl). You'll need the Griseous Orb to change it back into it's Origin Forme; the forme from the Distortion World.
After you beat the Elite Four, you'll want to go to Turnback Cave (located off of the Spring Path on Route 214). Once inside, it's a confusing array of rooms. It's a bit of a puzzle but it's not too difficult. Try heading up twice and off to the right until you hit what's known as a "thirty room count". You'll know you're in the right room when you see a small, dark portal glowing. This leads into the Distortion World.
It's pretty strait-forward from here. Just follow the path (hopping on the side platform) and you'll find the Griseous Orb. It's a hold item which increases Girtina's ghost/dragon moves and allows it to change into it's Origin Forme.
