Beat the elite four, go back to where Misty's city is. There is a road north, go up it. The is water at the end surf it once you get to a cave opening, there will be a cave and you search for Mewtwo
Better Answer:
You have to beat the elite 4 and then, you have to get the national pokedex from professor oak (must have caught 60 different pokemon) then you go to one island and talk to celio(he will ask u to get ruby and a sapphire for him)
Ruby: the ruby is located in mt. ember. when u get to the top, u have to go to the right and u should see 2 rocket grunts. battle them and go into the cave.
(the HM Strength is required)
once u have the ruby, take it back to celio and he'll give u a rainbow pass i think to travel to the sevii islands.
Sapphire: go to the dotted hole on six island. go up to the door and use cut and the door will slice open. when u get in the cave, follow the following directions to get to the gem
up, left, right, down.
once u reach the sapphire, a scientist will come and take it and leave. leave the dotted hole and go to the rocket warehouse. once u get there, u will have to get through the maze. once u get to the female rocket grunt on right (just ahead of where the entrance is) battle her and then she'll change one of the arrow panels where u can go out and go back in without going through the maze. then u go up to another rocket grunt. battle the grunt and then go up again and you will see the scientist that took the sapphire. battle him and he'll give u the sapphire. get out of the warehouse and go back to celio.
once u gave the sapphire to celio, u can go back to the kanto region.
When u get back, go to Cerulean City and go up onto the nugget bridge and surf down to where u see a cave. (where a guy was standing) go inside and find mewtwo.
hope i helped.
Chat with our AI personalities
yes
um listen Pokemon fire red does not have mew only mewtwo and that's in cerulean cave
Zapdos, Articuno, Moltres, Mewtwo, Entei/Raikou/Suicune (depends on what starter you chose).
Try filling your pokedex and show it to pro. Oak and he gives you sumthin
you will see mewtwo if you follow the maze you will need strength rock smash flash and surf