This Dream is the second opening for the dub and many of the clips are from the second Japanese opening for Advanced Generation, Challenger!! The opening debuted during the Pokémon Advanced Challenge episode "What You Seed is What You Get".
The opening starts with the Pokémon Advanced Challenge sliding into the center of the screen. Ash and Pikachu are seen in space in the next scene on a large rock as Rayquaza floats by them. The scene is followed with Ash in darkness with the light on the ground, similar to how it would appear when opening a door.
Ash and May battling in a large Pokémon stadium. Ash's Pikachu and May's Combusken charge towards a Hariyama and a Gardevoir. Pikachu jumps uses Thunderbolt on the Hariyama. The scene transitions to Ash running as Charizard, Venasaur and Blastoise are seen as he runs by.
It transitions to Ash, May, Max and Brock running on a dirt road with all their Pokémon as Shellow fly's over and up close to the camera. The next scene shows Ash, May, Max and Brock sitting on a hill as the camera rotates around them as Pikachu smiles and stretches.
Nurse Joy and Officer Jenny appear as Brock with heart-filled eyes bugs them until Max shows up and pulls his ears. Drew and his Roselia have a brief cameo as he throws the red rose he was holding.
Team Rocket blast off into the air quickly and end with their regular sparkle in the air as the opening transitions to some Pokémon battling and finally showing Pikachu who uses Iron Tail. The opening finishes with the Pokémon Advanced Challenge sliding into the center of the screen similar to how it appeared at the beginning.