Their isn't a key you need to beat oreburgh gym eterna gym veilstone gym and pastoria gym then Cynthia the Pokemon league champion gives you a secret potion to use on the pshduck blocking the way to celestic town give it to them and then go to Cynthia's grandmother she looks really old and give her an old charm what Cynthia gave you then battle to galactic grunt blocking the ruins and then go inside cynthias grandma comes in and tells you about mesprit uxie and azelf then go back to hearthome and fantina will be there.
where is the exact location of the key to open the petalberg's gym in pokemon perla not on pearl?
You must go into the cave in the south of town to find the gym leader in the back.
You defeat tem rocket
The Galactic Grunt in Pastoria City has it. You need to bet the Gym to get it.
The key to the gym
which key there are a ton
there is a key in the Pokemon mansion... you need it to get into the gym... search the Pokemon mansion thoroughly
You will find the key to the Gym of Cinnabar Island, From the Pokemon Mansion that is on the same island.
there is no key you buthead!
Get the key from the basement of the mansion next to the gym.
in the bottom of the Pokemon mansion
Find the secret key in the Pokemon Mansion,( Next to the gym)