The first episode of Christina's Pokemon Adventure.
Christina visits Professor Oak's lab to pick a Pokemon for her Pokemon journey. After some long thinking, she finally chooses Squirtle, who quickly takes a liking to her. All of a sudden, Blue Oak comes in and takes the Bulbasaur. When they go outside, Christina asks Blue why he didn't take Charmander, and he says it's because Bulbasaur has the upper hand over Squirtle and challenges her to a battle, which she agrees to. They battle, and Christina and Squirtle win, despite the type disadvantage. Blue bids farewell to her, and he runs off. Christina's journey begins, as well.
Professor Oak (debut)
Squirtle (Christina's; debut)
Bulbasaur (Christina's; debut)