Professor Oak joins Ash Ketchum and his mother as they travel to the Unova region. He accompanies the group to help Ash transition and observe new Pokémon species. During the flight, he witnesses the Legendary Pokémon Zekrom stirring a storm and observes Zekrom's lightning strike disable Ash's Pikachu's Electric-type moves.

Upon arrival, he meets Unova researcher Professor Aurea Juniper. He collaborates in analyzing the unusual Zekrom phenomenon and its effect on Pikachu. His presence bridges connections between Ash and the Unova research community. Throughout this visit, he demonstrates scientific interest in regional Pokémon variations and Legendary Pokémon manifestations. His role remains observational and supportive during this introductory phase of Ash's Unova adventure.