Beat the Elite Four. You cannot get Mewtwo if you don't defeat the Elite Four and become champion.Go to Island 1 and go to the volcano. You will need a Pokemon who knows surf to do this because it is on an island.Go to the entrance, and there you will see some Team Rocket soldiers chillin' out. You will hear the first password to the Rocket Warehouse (explained later). They will see you, so you will have to battle them.Once you have finished, go inside the cave entrance and proceed all the way down to the bottom level. You do not need to read the braille charts and all that. You will need strength to do this, so get a Pokemon who knows strength.Pick up the ruby. Then you can go outside using an escape rope. If not, then you will have to get out manually.1.Go to Island 6 and go to the Dotted Hole as shown on the town map you have. Go to the entrance, and it will say "cut" in braille. So, you will need a Pokemon who knows cut.2.Go inside, and look at the braille signs. If it has 2 symbols, it will mean "up." If it has 5, then its right. If it has 4, then it is either left or down. You can probably figure it out, but if you mess up you have to start over again.3.Proceed to the bottom level. Once you're there, you will see the sapphire. Don't get excited, because a super nerd will take it first. He will give you the second password to the Rocket Warehouse though.4.Go to Island 5 and go to the Rocket Warehouse. Defeat all the soldiers there.5.Search on the internet on how to get through the warehouse. You will have to defeat all the soldiers in there as well.6.Finish off the last soldiers, and at the end you will see the same guy again. Battle him. If you beat him, you will get the Sapphire.Give the gems to Celio. (the guy who operates the machine on Island 1) He will connect the regions of Kanto and Hoenn by signal (not important unless you are trading with a guy there).Go to Cerulean City. Then go to the cave where you will see that the man has gone. You will need surf to get to the cave. Go to Route 24 and get onto the artificial stream that connects the cave with Route 24. Go inside the cave, and there will be a lot of strong Pokemon thereGo through the maze, and at the end you will see Mewtwo. Catch him with the Master Ball. Now this is very important: Mewtwo is one of the most difficult Pokemon to capture, but that doesn't mean it is impossible to catch him with an ultra ball. If you used your master ball, you must stock up 50-65 ultra balls and SAVE. Once you have captured him, you are free to go.