Access to:
North: Flower Paradise
South: Route 224
Accessing this area requires obtaining the Oak's Letter and speaking with Professor Oak on Route 224. The Oak's Letter was only available via a Mystery Gift download for Platinum. The Oak's Letter can be obtained with hacks or cheats, and Flower Paradise to the north is itself accessible in Diamond and Pearl with the use of a glitch.
This area has no Pokémon, items, or Trainers, and exists to connect Route 224 with the Flower Paradise.