Oooh.. that's difficult. Very difficult. Very very difficult. Very very very difficult. Very very very very difficult. Very very very very very very very very very very very very very difficult. You need to have caught Suicune, Raikou AND Entei on your Crystal cartridge, and have them in your party, and then you must talk to some person somewhere in Kanto, poor Sentret never met him and doesn't really know who, and he'll give you a wing to go battle Ho-oh! Good luck! HUG!!!