C420 Don't Tell Me?

What was it that was so mysterious that people couldn't figure it out?

"You can do it with just a few people. My Emei Sect Mountain Gate is wide open, I welcome your arrival. However, there is only one person who can do this. Even if he does come, he can only wait outside the door. Don't even think about entering the Emei area. " The Emei Sect Master said indifferently