Treecko made her debut when Sarah and Gabrielle were walking to the Petalburg Gym. Team Rocket attempted to steal Sarah's Treecko, Azurill, Skitty, & Whismur to take to the boss, but the Pokemon were rescued by their trainer and Gabrielle who sent Team Rocket blasting off. After their battles, Sarah and Gabrielle bid each other goodbye.
Treecko is very caring and friendly to her trainer and other Pokemon. She cares about everybody.