Pokémon: Black & White: Adventures in Unova and Beyond - Cilan and Brock!! Gyarados's Outrage!!

デントとタケシ！ギャラドスのげきりん！！

Synopsis & Overview

Dent and Takeshi! Gyarados's Outrage!! is the first spin off of the Best Wishes series of the Pokémon anime. (Source: Bulbapedia)