To catch mew you have to go to cerulean city and you need an abra, beat all trainers on nugget brige then go left DONT GO DOWN not yet. ok so there is grass downwards on the right take one step down and INSTANTLY press start and teleport back to the cerulean pokecentr cross nugget brige again but go right this time (by now you will notice your start button does not work dont panic) there is a junior trainer with his back 2 a rock beat him and teleport again go to cross nugget brige as soon as the colour changes when u leve the city press start AND THEN YOU FIGHT M E W!!! he is lv 7 but u will need lots of pokeballs 2 get him.