Pokemon The Series: HeartGold and SoulSliver

 is the 13th season of the Pokemon anime, following Pokemon DP: Galactic Battles and preceding Pokemon DP: Sinnoh League Victors.

Plot
Ash, Brock and Dawn decide to take a break from Sinnoh and take a trip to Johto instead, where they meet "all-new" Pokemon.

Trivia

 * The Johto seen here is closer on the ones from the titular games than the original Gold/Sliver games.
 * Porygon-2 and Porygon-Z finally make anime appearances here.