you half to go to Celadon city and get the tea from the old lady in the masion.(you can also get evee from the old man their.)When tou get the tea go to the gaurd that said the road was closed and give him the tea. then tou will be allowed in. After that go to the big building and when you get insind keep getting on teleport squares untill you reach the place with team rockets leader and battle him. If you win team rocket will leave saffron city and you will be able to enter the gym and battle for the marsh badge, in adition to getting a master ball. If you lose you half to do the whole thing over again! GOOD LUCK!

what he said