What do you do after you beat the fourth gym on Pokemon pearl?

Answer 1

This really had me stumped for a while, but I finally got it. See that Team Galactic guy in front of the Great Marsh building? Talk to him, and you'll hear him talk to himself. He'll run off and say, "Don't you follow me!" Your video game instincts will tell you to follow him anyway. So follow him, and you will find him on the other side of the little building he ran through. Talk to him again. He will run off again. This time he'll be by the beach. Then he'll do it again, but he runs up to the hotel. You won't see him at first, but he will be at the end, by the lakefront. Then he will leave, but you can't follow him. You'll find Cynthia, and she'll give you the MagicPotion that will clear the Psyducks in the way of getting to Celestic Town. Cynthia will find you and ask for a small favor: to go to Celestic Town, find her grandmother, and give her the charm. To find Cynthia's grnadmother, you have to battle the Team Galactic guy. Go in the ruins when you're done. You'll find Cynthia's grandma with you and she'll talk with you for a bit. Then go to Hearthome City and battle Fantina!