I like Bacon on 03 August 2009
1. Go to Jubilife City
2. Go to the TV building, 3rd floor.
3. Talk to the bottom clown.
4. Insert this message:
EVERYONE HAPPY
WI-FI CONNECTION.
5. Mystery Gift is unlocked, save the game, and soft reset.
6. Select Mystery gift and make sure you select the online option.
National Dex required to get Darkrai, but not required to start the event. But to get him, yeah, you will need the national dex.
http://www.pokemonplatinum.com/#/pokemon/darkrai/
