The official Japanese Pokémon YouTube account has posted a trailer for the upcoming episode
Pocket Monsters XY Special: The Strongest Mega Evolution ~Act I~ (ポケットモンスター XY 特別編 最強メガシンカ ~Act I~) that airs on April 3th, 2014. For more details about this special,
read our previous article.
The Strongest Mega Evolution ~Act I~ Trailer
Source:
http://www.youtube.com/watch?v=qnzdXEkKEtI