Mt. Battle is a place where 100 trainers await you to battle. Cipher has commanded an attack here, led by Cipher AdminDakim. Dakim is on Zone 10. You have to face nine other trainers before you get to him.
Before you do anything…go back and save! On the tenth Zone stands the self-proclaimed "mighty" Dakim. You now get another cutscene. Dakim and the Area Leader, Vander, are talking. Dakim punches Vander because Vander won't give up the Time Flute. Eventually, Dakim sees you and battles you.
After all is said and done here, Dakim will be mad at his loss. Skrub and a female Cipher Peon will come over. Dakim tells him to go back to the Shadow Pokémon Lab. After Skrub leaves, and after some conversation, Dakim leaps off the platform. No really, he does a backflip.
Anyways, pick up the shiny thing on the ground. It's the F-Disk. The purpose of this will be explained later. Talk to Vander and he tells you why Cipher attacked. You'll soon find yourself at the reception counter of Mt. Battle. Vander hands you the Time Flute. There are only three Time Flutes throughout the whole Orre region. Use them wisely! Now go and withdraw Entei and save! In the room, there is a chest containing TM47 (Steel Wing).