I've herd a hundred things about this Pokemon in canalave city and that..

A nintendo event is a thing that nintendo has every blue moon. When you go to them you need mystery gift.

Nintendo will hold them every once in a while.

A Nintendo Event is a usually annual event that could take place somewhere in America, Japan and other big-time countries except Canada. When you arrive at the event grounds, there is generally where you can wirelessly hook up to a computer or something, and a special event-only Pokemon (like Surf Pikachu, Jirachi, Shiny Zigzagoon, etc.) will be transfered to your game. Sometimes, instead of a Pokemon you will receive an item (such as the Aurora Ticket, Azure Flute...) which will allow you to reach an area where you can find a legendary Pokemon.

In the case of that house, it is most likely that you must receive an item to open that door, or it's a door that was never meant to be opened.

Yes it is darkrai and it is were you get some really good Pokemon in this game and either an action replay or go to a nintido convention