After the dramatic events unfold in the Team Galactic HQ in Veilstone City, you venture through Mount Coronet to reach the summit.

Reach the Upper Levels of Mount Coronet

If you haven't already, use the Town Map to fly to Hearthome City. Go southwest in the city and use the gate that goes west to Route 208.

In Route 208, go west, then north up the stairs, then west, then south to where you can see a hiker. Go west from there and enter the cave.

Go south and use Rock Smash on the rocks in the way. When you reach two sets of stairs, go down the south stairs, then Surf east to get a Dawn Stone.

Surf west again, then go north up one set of stairs. From there, go west, then north until you reach some water near a door. Surf east on the water, then go south down the stairs to reach a bottle of Protein.

Go back north up the stairs, then go east. Carefully use the control stick (not the directional pad) to slowly go south until you can go east. Use Rock Climb on the rock ladder on the wall. Then go north and up the stairs.

Mount Coronet - 2F

In this part of Mount Coronet, you can catch Bronzong, Bronzor, Chingling, Clefairy, Golbat, Graveler, Machoke, and Medicham.

Go north, then west, and up the stairs. Go to the right and pick up the Max Potion. Then go west and check on the rock to find a hidden Ether.

Go south down the stairs, then west, then as far south as you can go, to find an Escape Rope.

Go northwest and up a short flight of stairs. The path splits. Go southwest and you find an exit to the outside. Go outside, go south, and use Rock Climb on the rock ladder, then go west to find a bottle of Iron. Then go back the way you came to enter the cave.

Go northeast, and keep going north to reach a wooden bridge. Go west across the bridge, then follow the path down some stairs. The path splits. Go south up some stairs and you will get a TM80 Rock Slide at the end.

Go north until you see an item to the left. It is a Revive.

Go east and cross the wooden bridge. On the other side, go south down the short flight of stairs. There are one-way ledges to the south that you can jump down if you need to leave the cave. Otherwise, go west from the short flight of stairs and follow the path to a cave door. Go in.

Mount Coronet - 3F

Go north, and go up the stairs. Then go east and down the stairs. Go south and check on the rock to find a hidden Max Revive. Then go north and up the stairs.

Go north and you can battle Team Galactic Grunt who has a level 40 Beautifly. You get 1760 Pokédollars for winning.

Go west and check on the rock in the northwest corner to find a hidden Super Repel.

Go south and you can battle a Team Galactic Grunt who has a level 39 Bronzor. You get 1716 Pokédollars for winning.

Go south and you will be outside. Go east. You can avoid the grass by going up the stairs, but there is a hidden Full Heal in the grass.

Follow the path and you will reach a rock ladder in the wall. Check on it to climb up it with Rock Climb. There is another rock ladder straight ahead. Check on it to use Rock Climb. Then go east and check on the rock in the grass to find a hidden Nugget.

Go back down the rock ladder, then go east and enter the cave.

Go west to the water, and break the brown rock, then check the wall where the rock was, to find a hidden Tiny Mushroom.

Go east, then north up the stairs and check on the rock to find a hidden Ultra Ball.

Go south to go back outside.

Go west. If you go all the way west, there is grass to the south, but you can avoid it by going south on the snow to the right of it. Check on the silvery rock and you will use Strength, allowing you to push it south out of the way.

To the southwest, there is a brown rock that you can break with Rock Smash. Afterward, you can go north and check on the rock to find a hidden Max Potion.

Go north from there to find a cave entrance. Go in.

Go north and check on the rock ladder to use Rock Climb.

To the northeast, you can battle a Team Galactic Grunt who has two level 35 Dustoxes and a level 38 Golbat. You get 1680 Pokédollars for winning.

Go west from the grunt and use Rock Smash on the rock in the corner, then check on the rock to the left to find a hidden Revive.

Go east and check on the second rock along the north wall to find a hidden Ether.

Go east and you can battle a Team Galactic Grunt who has a level 38 Stunky and a level 38 Golbat. You get 1672 Pokédollars for winning.

Go south and down the short flight of stairs, then go to the left and check on the rock to find a hidden Escape Rope.

Go east from there and exit the cave. Go east, then north. In the grass to the north, there is a hidden Rare Candy on the rock.

Check on the rock ladder on the left to go up with Rock Climb. Go west over some short flights of stairs, then check on the rock to the south to find a hidden Tiny Mushroom.

Go west from there, then north up two short flights of stairs, then go east and check on the rock at the end to find a hidden Big Mushroom.

Go west from there, then south up the short flights of stairs, then go south and enter the cave.

Go south and check on the southern rock to find a hidden Tiny Mushroom.

Go east and up the stairs.

Go south and you can battle a Team Galactic Grunt who has a level 38 Bronzor and a level 38 Glameow. You get 1672 Pokédollars for winning.

Check on the rock to the right of the grunt to find a hidden Max Potion.

Go south and you can battle a Team Galactic Grunt who has a level 37 Bronzor and a level 37 Golbat. You get 1776 Pokédollars for winning.

Check on the small rock southeast of the grunt to find a hidden Stardust.

Go west and up the stairs.

Go north and you will battle a Team Galactic Grunt who has a level 37 Golbat, a level 37 Bronzor, and a level 37 Glameow. You get 1776 Pokédollars for winning.

Go north through the door.

Go north and walk between the two grunts. It's not possible to battle them separately. The two Team Galactic Grunts have a level 38 Stunky, a level 38 Dustox, a level 38 Glameow, and a level 38 Croagunk. You get 3344 Pokédollars for winning.

Go north and there will be a cutscene. Afterward, go north and you will have a double battle against Commander Mars and Commander Jupiter, with the help of your friend, whose pokémon include a level 42 Munchlax and a level 41 Staraptor. Mars and Jupiter have two level 41 Bronzors, a level 46 Skuntank, a level 45 Purugly, a level 41 Golbat, and a level 42 Golbat. You get 7644 Pokédollars for winning.

Afterward, your friend will fully heal your pokémon, and there will be a cutscene, and you have to battle Team Galactic Boss Cyrus, who has a level 45 Honchkrow, a level 45 Gyarados, a level 48 Weavile, and a level 46 Crobat. You get 8832 Pokédollars for winning.

Afterward, there will be a cutscene. You can save the game. Be sure to heal up your pokémon. You can't leave the area. Go north and check on the legendary pokémon, and you will battle it.

Dialga/Palkia

If you are playing Brilliant Diamond, you will battle Dialga. If you are playing Shining Pearl, you will battle Palkia. This legendary pokémon is level 47. You can defeat it or try to catch it. You can use the Master Ball on it, or save the Master Ball for later so you can use it on another pokémon. If you do defeat it, it will reappear here whenever you defeat the Elite Four and Champion for the first time, or you defeat them in rematches. It only stops reappearing after you catch it.

Afterward

Afterward, go north and you will find either the Adamant Orb or the Lustrous Orb at the north end of the temple area. If you caught the legendary pokémon, it can hold the orb to make its attacks more powerful.

Your next destination is Sunyshore City. You can't use Fly or an Escape Rope here, so go south into the cave. You can either use an Escape Rope if you have one, or you can go back the way you came until you reach a snowy outdoor area. You can either use Fly to go to Veilstone City or Pastoria City, and from there make your way through Valor Lakefront to reach Route 222 to the east, or if you skipped the eastern cave in this area, you can go east and down a rock ladder with Rock Climb, then go east into the cave there.

If you went into the cave, go north and check on the rock ladder to use Rock Climb. Go east, then south up the short flight of stairs, then use Rock Smash to break the brown rock on the left, and check the wall behind where it was to find a hidden Max Ether.

Go west, then south up the short flight of stairs. Go east and check on the rock to find a hidden Big Mushroom.

Go west and down the short flight of stairs, then go east and down the short flight of stairs. Go west and then north on the rock ladder using Rock Climb. Go north, then east down the short flight of stairs. Then go south and then east up the short flight of stairs. Go north and check on the rock to find a hidden Revive.

Go south, then west down the short flight of stairs. From there, go north. Use Rock Smash on the boulder north of the short flight of stairs, then break the next boulder to the north, and check where that boulder was to find a hidden Rare Candy.

Use Rock Smash on the rock to the left, then go north. Use Rock Climb on the rock ladder on the left, then go north. Check just north of the base of the flight of stairs to find a hidden Nugget.

Go west up the flight of stairs, then go north and use Rock Smash on the rock. Check where it was to find a hidden Full Restore.

Go south, then east down the stairs, then south and use Rock Climb to go south down the rock ladder. Then go east, then north until you go through a cave door.

Follow the path and get the TM02 Dragon Claw that you find in the corner.

Go slightly north and check above the two rocks to find a hidden Hyper Potion.

Go north and you will reach a silvery boulder. Check on it to use Strength, then push it north. Then you can go east and north to leave the cave.

Fly to go to Veilstone City or Pastoria City, and from there make your way through Valor Lakefront to reach Route 222 to the east.