After you have beten the final mission ( Mission 10 ) go back to the Foire temple and go to where all of the Go-rock squad grunts were. When you get close to the top, there will be a man with 2 Drowzee there. AND MAKE SURE THAT YOU ONLY AHVE 3 FRIEND POKEMON!!! Talk to the Drozee man. He will tell you if you wanna do capturing again, say YES. then the Drozee will put you to sleep. When you wake up, the Drozee man will be gone and you will be back in the middle of the mission! You will be able to capture Entei, Suicune, and Rikou again!