Water Stone in Pokemon Black?

Where can i find a water stone in Pokemon Black

 

In the 5th gym city, near the gym, you can surf to a small island with a lighthouse. The item on said lighthouse is in fact a Water Stone.

 

Wait im at the 5th gym where do i get surf???

 

You get it further on from Adeku.

 

Once you leave Sky Arrow Bridge and enter Hiun City, visit Pier 1 (left-most) and talk to the scientist. Choose the first option for a Leaf Stone, second for a Fire Stone or a third for a Water Stone. This will work only once (you can't take all three items)

 

how i can download the games ,help me plz

 

Look in the NDS Trading section.