Go to cold storage to find team plasma
you need to beat clay. and in order to enter his gym, you need to defeat team plasma in the ice storage (or something) south of driftveil.
In the building across from the pokemon gym
it is at driftveil city
im not shure where exactly to get a max revives but i do know that you can get revival herbs at driftveil city. at the driftveil market
They are in cold storage below Driftveil City
Go to cold storage to find team plasma
In Driftveil City, you will find Team Plasma in the cold storage. Once you defeat a guy who is studdering from the cold, go to the left and you will see an open crate. They are in there. ;p
You need to Team Plasma out of the Cold Storage in Driftveil before Clay will face you.
you get it when you beat your friend Binica in driftveil city.
Team Plasma can found in a multitude of places: The 'bases' (' ' because it's just the Plasma Frigate) are: PWT Driftveil, Route 21 (Right hand side of Seaside Cave) and Giant Chasm. Although you find Plasma members elsewhere like Opelucid.
You do not defeat Team Plasma in Striaton City, you will need to defeat them in the Dreamyard.
after you defeat Elsia, go west and meet her at the bridge. you will get lead across a bridge and there you are in Driftveil city :)
you need to beat clay. and in order to enter his gym, you need to defeat team plasma in the ice storage (or something) south of driftveil.
Win
You go down route 6
Oh you just need to battle with team plasma. Then with all the event with team plasma done for NOW in Castelia City Burg can finally battle you!