Pokemon Heart Gold and Soul Silver - Walkthrough - Route 28 Pokemon Heart Gold and Soul Silver: Walkthrough - Route 28
Head left, through patches of grass. Go across the top, and when you reach a fork, go down, then left, and up a stairway.

Continue left, going down under the ledge, to see another stairway, go up this one as well.
This walkthrough was written by MKaykitkats, used with permission.