After you make it through Route 4 and meet Milo, you arrive in Turffield.
As you enter the town, you will meet up with Hop.
East of the Pokémon Center, there is a sparkle along the north edge of the path. Check on it to get an Energy Root.
If you go east from there, then west at the split, then southwest at the next split, check on the sparkle near the stones to get an Everstone.
If you go northwest from there, you can go toward the northeast fence to find TM97 Brutal Swing.
Go east from there, then southwest from the large stone to return to the Pokémon Center. From there, go north, then west past the flower shop, and follow the path to find a Max Revive.
Go back to the Pokémon Center, then go west. When the path splits, you can go west, then southeast, to find a sparkle. Check on it to get a Leaf Stone.
Go back to where the path splits and go northeast, then northwest to find 3 X Attacks.
Go back again to where the path splits, then go northwest to meet up with Sonia. You get Milo's League Card and 2 Revives.
Go to the east side of this hilltop and check on the sparkle in the blue fountain to get a bottle of Fresh Water.
The girl at the entrance of the hilltop tells you a riddle:
"Seek yourself three standing stones,
with Grass before the other ones.
Use well that strength, and find then
the strength of its strength in the end.
Dally not, if you've a mind
To find what time has left behind."
You will notice if you check on the stones throughout the town that they have types written on them, like Poison, Dark, Grass, etc. The riddle has to do with those types. To solve the riddle, , ,
When you are ready, go to the Stadium. After a brief meeting with Hop, go into Turffield Stadium.