After Ash and Officer Jenny escaped from Team Rocket, they went back to the camp site to look again for Pikachu. They did not find him, but they did see a little Chikorita spying on them. They feared it was team rocket, and they left after it did.
Moments later, Pikachu came bounding out into the clearing. He saw the charred logs in the fire pit and the tent was still set up. He looked around, calling for Ash - but he did not see him. He sadly ran back to the stream, and Chikorita was surprised. "Chika chika, chikorita?" Which translated to, "They were there. Did they leave?"
Pikachu sighed. "Pika pika," he shook his head.
Pikachu looked off into the distance with a lonely face. He had a good life now, and a friend. He had food and clean water and a place to sleep. He might never find Ash, but if he did, would he leave this life now? Abandon his new friend? Besides, Ash didn't do anything in attempt to go after Team Rocket when they took him. Ash has other pokémon, but Pikachu was always the favorite. Well, he could favor his other pokémon. Pikachu decided to start fresh and forget about Ash.
Chikorita tapped Pikachu lightly on the shoulder, and he was woken from his deep thinking. She asked him if he was alright, and he simply answered, "Pika," which meant, "I'm fine."
Ash and Jenny began to head down the path that the little Chikorita ran down. They soon heard Chikorita's voice, and after a few more steps, another pokémon as well. Ash recognized it first. "Pikachu! Pikachu! It's me, Ash! Pikachu!" He yelled as he bolted into the clearing with a huge smile on his face. Pikachu's face lit up, but then faded as he turned his back to Ash.
"Pikachu! I missed you so much! Are you okay?" Ash started firing questions at him, then his voice quieted when he realized Pikachu was not paying attention.
"Pikachu? C'mon, let's go home. Is everything alright?"
Pikachu did not look back.
"I'm sorry I didn't go after you. Will you please forgive me?" Ash began to tear up as he wrapped his head around the fact that Pikachu might not want to go back with him.
Still no answer from Pikachu.
"It's okay, kid. people move on, and I'm sure you will too. Pikachu is happy now." Jenny turned Ash around and put a caring hand on his shoulder.
Pikachu tried to forget Ash, but Ash couldn't forget about Pikachu. They were best friends and they went everywhere with each other. Ash couldn't let his best friend get stolen and not even try to do something about it. They were like brothers, but Pikachu moved on.
"But I don't want to move on," Ash looked back sadly and walked back into the woods.