Cerulean cave
You can't get mew in firered or leafgreen.
Its not possible to get mew in firered only emerald can via Nintendo event.
You can't catch it on Firered you can only catch it in Emerald
Pokemon firered emerald
Nope, you have to trade him.
The Cerulean Cave
sadly,no
can't but you can get one from emerald if you have the old sea chart and catch mew at faraway island.
No, you to migrate it from Pokemon firered/leaf green.
Unfortunately, Mew is not a catchable Pokemon in FireRed. It is impossible to catch it without a Cheating Device. Sorry, The interwebs fooled me, too.
No you caan only send it from firered or leafgreen
Put it to sleep then use an ultra ball.