First thing is first - good luck trying to find a video because all links to it are being blocked and made Japan only. So are rehosted efforts of it, so don't count on seeing it.
edit: http://www.dailymotion.com/video/xquxz9_pokemon-black-white-2-anime-promo_videogames someone just linked me so enjoy if it's still viwable when I post!
Lucily someone posted the link on sppf to the video before it had been properly blocked, so a few of us who clicked it early enough (including me) got to see it before it was blocked. It's basically a anime-style video of scenes that seem will be in the game (idk how accurate they will turn out to be, but one can assume it's possible some aspects of the game are in that video). It's also decently animated and seemingly by some different studio.
Have this rough summary of what happens too if you cannot see.