Which episode in Pokemon Black and White is Zekrom in?

Zekrom is not in Pokemon Black and White, he's in Pokemon Black and White 2, specifically in Episode 1, "The Hero of Truth!".

Here's why:

* Zekrom and Reshiram are legendary Pokemon tied to the Black and White 2 games. They're not featured in the original Black and White.

* The first episode of Black and White 2 focuses on the arrival of these two legendary Pokemon. They are central to the story of the new games.

So, if you're looking for Zekrom in Pokemon anime, you'll need to watch Black and White 2!