Heading towards the White Ruins, Ash and co. come across a special Kanto Fair, a fair celebrating the region of Kanto and the various Pokemon that dwell there. Ash is excited to see all these attractions that remind him of home and ends up seeing a cheerful Charmander right on stage. Reminding him of his old friend after telling his stories to them, Ash calls Professor Oak and requests that he sends over Charizard (since he came back from Charific Valley) while he sends Unfezant to his lab. However, once there, Charizard soon meets Iris' Dragonite and a fierce rivalry between them begins with a battle. Will the battle last? Who will win?
Iris thought that Ash's Charizard was a Dragon-type because it used Dragon Tail at first until Ash's Pokedex corrects her that he's a Fire/Flying-type Pokemon.
It is also the reason why Iris couldn't have him herself since Charizard's not an actual Dragon-type at all.
All the characters in the flashbacks, except Koga, have had redesigns to fit the BW series.
Although Ash and co. (minus N) had encountered some of the Pokémon that are from Kanto they know in Unova.