This is not Valid anymore so you cant get it
This will help you get Darkrai read steps
1.Have a DS(anykind)
2.Have a verson of pokemon black or white
3.Start the game
4.go to main menu(NOT THE CONUTINE)
5.Go to Mystery gift
6.Go to Recieve gift
6a.You need to at least have WFC(Wi-fi Connection) Internet connected to your DS
7.Go to Nintendo WFC
8.Wait for like 1-2 min or sec to connect
9.You will see "It's Darkrai"
9a.You need to at least have a 11 wonders cards bellow(you can not get Darkrai if you have 11 wonder card)
10.Click "It's Darkrai"
11. Go all through the crap Darkrai has in its wonder card
12.Restart the game
13.Go to continue
14.Go to Poke center
14a. Need to least have a open slot in your party to recieve Darkrai
15.Talk to the delivery man(Hes in blue)
16.DADADADADADA You have Darkrai.
17?. WARNING: NINTENDO WAS NOT BEING NICE AND PUT HIM ON LVL ******** 50!!!!
Ok bye :)
hope this helped