Pokemon X and Y Walkthrough: Dendemille Town
Professor Sycamore and Dexio stop you to talk about a legendary Pokemon, Xerneas or Yveltal depending on your game version. The Pokemon Center is located to the south. Mr. Bonding is inside waiting to give the Accuracy O-Power. There's also an orange-haired girl that gives away a Sitrus Berry, which heals 25% of the user's max health. The Hex Maniac in front of the Pokemon Center sells Moomoo Milk.
A Big Root can be found in the field east of the Pokemon Center. It increases the HP gained from moves like Giga Drain and Leech Seed. The house north of this field is where the Move Deleter and Madam Reminder live. Just like his name suggests, the Move Deleter can delete any move from a Pokemon's arsenal, even HM moves. Madam Reminder can make a Pokemon relearn any move they learn naturally through leveling up. Madam Reminder charges one Heart Scale for her services but the Move Deleter is free.
The house northeast of the windmill has a man inside that gives a Shell Bell if you've seen 70 or more Pokemon from the Moutain Kalos Pokedex. Whenever a Pokemon deals damage while holding a Shell Bell, it heals itself for 1/8th of the damage dealt. A woman in the house southwest of the windmill gives a Leppa Berry daily if you show her a specific TM. The Youngster in the same house gives TM 42 Facade, which deals double damage if the user is Burned, Poisoned, or Paralyzed.
With Dendemille Town fully explored, head north to the Frost Cavern.