You need to talk to celio and then go to mt. silver and battle the team rocket guys and then go in the cave and it is not to far in the cave once you get it go back to celio and give it to him
After you beat the elite four, wally is in the victory road cave, just inside exit. You can still battle him there from time to time.
maby you have a old version of Pokémon LeafGreen and when it came out , the Cerulean Cave wasn't finished.
you have to get a national dex by searching for all the pokemon.
no it doesnt all that happens is that you go back to pallet town and then you can get mewtwo in the cave
You have to beat elite 4 to get into Mewtwos cave
it is a mountain
Beat the elite four and if he is still there obtain at least 60 pokemon data
After you beat the Elite Four.
You have to beat the elite 4.
beat the elite four.
Altering Cave apears on route 103 after you beat the Elite four.
Beat the elite four the cave should open.