When is the next secret key event for Pokemon platinum?
check serebii.net for info on upcoming events for Pokemon Diamond,Pearl,Platinum.
The final deoxys event for Pokemon platinum ended. It was a download mission in Pokemon Ranger Guardian Signs. You had to do it with 4 people. If you have the mission downloaded then you can get a deoxys everytime you beat the mission. Also to be able to play the mission you have to unlock the past missions in POkemon Ranger Guardian Signs.