Japan Phase 1 Distribution: September 30, 2008 ~ November 4, 2008
Japan Phase 2 Distribution: January 16, 2009 ~ March 2, 2009
US Distribution: April 20, 2009 ~ May 12, 2009. Step 2 will NOT work until then!
This guide is still relevant for the US Secret Key distribution, although Step 2 will not work until the distribution period.
Step 0: Prerequisites-
Make sure you're playing the actual game on a physical DS, not an emulator. You can download the Secret Key from anywhere in the world.- Complete Eterna Gym and make sure one of your Pokémon can use HM01: Cut.
- Set up your Nintendo Wi-Fi Connection so that you can access Mystery Gift.
- Obtain a Rotom (there's one in the Old Chateau) and put it on your team.
Step 1: Unlocking Mystery GiftHead to the Jubilife TV Building.

Take the elevator to the third floor.

Speak to the couple as pictured here:

For the first keyword, select
minna (EVERYONE) under the
hito (people) category.

For the second keyword, select "HAPPY" under the
kimochi (feelings) category, and confirm your selections.

For the third keyword, select "WI-FI" under the "Union" category.

For the last keyword, select
tsushin (communications), also under the "Union" category. In the English versions, the word is "CONNECTION."

The guy will tell you that you're a trainer who has connections and is "in the know." Mystery Gift has been unlocked!
Step 2: Receiving the Secret KeyWhen you reboot your game, you should see a new option on the main menu. Select
fushigina okurimono (i.e. "mysterious gift")

Select the first option,
okurimono uketoru, i.e. "receive gift"

Now, select the third option,
Wi-Fi de uketoru, i.e. "receive via Wi-Fi"

If you set up your Wi-Fi Connection properly, you will receive the Wondercard. It says (translated)
"Secret Key Present"
Receive it from the mailman in the friendly shop (PokéMart)
Part 3: Transforming your RotomOnce you've received your Key from the green-suited deliveryman, head to the Team Galactic building in Eterna City.

Walk up to the wall in the northwest corner and press A.

The Secret Key will unlock a new passageway.

Walk up to any of the appliances and Rotom will transform. A dialog box will pop up if your Rotom knows four moves, prompting you to delete a move so it can learn its special "forme-exclusive" move.

Prof. Rowan will enter the room and marvel at the discovery.
