How do you get Sacred Ash the item in Pokemon Platinum?

To get the item Sacred ash in Pokémon Platinum, follow these steps:

1. Go to the Fight Area.

2. Walk to the top left corner of the Fight Area.

3. Talk to the Old Chateau guide standing outside.

4. Enter the Old Chateau.

5. Go through the maze to find the girl.

6. Talk to her.

7. Leave the Old Chateau.

8. Go back and talk to the Old Chateau guide.

9. He will give you the Sacred Ash.