Remember why you came here in the first place? To warn the Mayor about Cipher's attack before they strike! Head to the Mayor's House, it's to the left of that giant circle place called the Pre-Gym. Head inside. The secretary won't let you upstairs into the Mayor's room, so you'll have to find a distraction. She says she'd like some music, so head outside and now head to the building to the right of the Pre-Gym. Inside, the man has... whaddya know... music! He'll let you have it, so take it back to the Mayor's House. Give the CD to the secretary. She plays the music, leaving the entrance to upstairs wide open. Sneak up there while the secretary listens to the music.
The Mayor isn't upstairs, but there is a note on the bed. Read it. It's a note from the Mayor to Justy, telling Justy of Cipher's plan. The note appears to have been cut short. You'll find the secretary standing right behind you. She'll do a little jig and... OMG it's a Cipher Peon in disguise!
Head outside, and you'll see something you don't see everyday. Justy walks out of the Pre Gym... six times. Hmm, six... six... where have I heard that number recently? They do their theme song, which sounds very familiar... It's the Hexagon Brothers in disguise! Track down all six of them around town. Each of them drop a little reward. They'll have their Shadow Pokémon if you missed them.
Resix is just outside the house where you got the music. He'll reward you the Battle CD 19.
Blusix is right outside the entrance to the city. He'll reward you the Battle CD 16.
Greesix is just outside of the Mayor's House. He'll reward you the Battle CD 28.
Purpsix is just outside the Pre-Gym. He'll reward you the Battle CD 08.
After they're dealt with, Fostin will spill the beans. All of the townsfolk that have been impersonated are in the Pre Gym's basement. You'll need the Elevator Key, which Fostin nor anyone else so far has... Head outside and talk to the little boy. There's commotion up in Phenac Stadium, at the farthest north in the city. Head there. On your way there... BAM! another Cipher Peon.
Snagging Snattle's Lunatone will be tough, and his Metang is devastating. He's not that hard, but still.
After beating Snattle, he will run off on national television! Pick up what Snattle dropped. It's the Elevator Key. With great haste, head to the Pre-Gym, use the Elevator Key on the elevator, and you can free the innocent citizens. After lots of chit-chat, Justy will ask for your P☆DA number. Give it to him, and voila. He'll give you a hint that there's a few shady characters going somewhere in the desert.
The Day Care is reopened. Yippee... *yawn*
Head to the Mayor's House and he'll thank you for defeating Snattle. He'll give you the beloved Exp. Share, quite rare in Orre. There's also Battle CD 27 and Battle CD 32 laying on the ground for you to pick up.