Rebecca was first seen watching the battle on the road between Anthony's Hitmonchan and Pikachu. After the battle she introduced herself to Ash and his friends and told them that her father
Anthony's holed himself up in the mountains and wouldn't come home at all despite the pleading from her.
Ash Ketchum and
Brock agreed to enter the tournament in order to beat
Anthony so that he'd come to his senses and return home to his family.
In the P-1 Grand Prix tournament,
Rebecca sat in the stands with
Misty as they watched all the fights hoping that her father would loose. After loosing,
Anthony asked his daughter
Rebecca to forgive him for worrying so much and they quickly made up. Thankful for
Ash Ketchum's help, she waved goodbye to
Ash Ketchum and his friends after
Ash Ketchum released his Primeape to her father.