You need to have got the fifth gym bage which I think is in pastoria city. Then there should be a galactic grunt guy outside the marsh/safari and you have to talk to him. He should run away and you have to follow him until he battles you. After you beat him, cynthia should come and give you some sort of potion that heals those psyducks and make them move. Carry on that road to celtic town (I think it is called celtic town. Not quite sure). You need defog to get there with ease though as it is really foggy and loads of stairs which are hard to see and trainers are there as well which you can´t see. Find this old lady which is the grand mother of cynthia and you will give her some sort of charm that you were asked to give her by cynthia. There should be a guy threatening to blow up these ruins so beat him up and then go in them. There will be some wall markings saying something like ´there was one which was made to two and those two were made into three´ and something else I can´t quite remember. Then you should be able to get to canalave city. It may not be correct as there is a bit about having to go to veilstone city and go into the big building there. You need a key and there should be a galactic grunt outside looking towards the big antennae thing. Speak to him and he will run away revealing the key to get inside. You should meat the boss of team galactic there and you have to battle him. When you win, he gives you a master ball. Strange if you ask me. I think you need to do this bit after you go to celtic town but I don´t quite remember. I do know you have to go to celtic town next though.