To make this story realistic Ash will be 16 years old and Red will be in his mid 30s. All of Ash's friends and rivals will be 16 except for Brock, Tracy and Cilan who will be 18.
Ash was relaxing across several chairs on the airplane back to Kanto; reliving the moment when he had defeated Trip in the final of the Pokémon league. Both trainers were on their last Pokémon; Trip had his Serperior while Ash had his Pikachu. Both Pokémon were at full health and ready for a tough battle. The battle between their two best Pokémon lasted for what seemed like an eternity; both not wanting to lose this battle for their trainers. Finally Ash had ordered Pikachu to use a thunderbolt on the electro ball that the Pokémon had just launched. The thunderbolt enhanced electro ball scored a direct hit right in the face of Serperior. Once the smoke had dissipated everyone could see that the Serperior had been knocked out. Both trainers couldn't believe it. The crowd couldn't believe it. The whole stadium was silent but then the referee yelled, "Trip's Serperior is unable to battle – Ash's Pikachu is the winner which means that Ash Ketchum from Pallet Town in Kanto is the winner of this years Pokémon league." Then the whole stadium erupted in celebration and fireworks soared into the sky. Ash ran onto the field straight to his Pikachu, who was also running as fast as he could towards his trainer. They hugged with tears in their eyes. They had done it, after four failed attempts at winning Pokémon leagues around the world; they had finally done it. Ash opened his eyes just in time to see Trip take a photo of the crying duo. Ash stood up and walked over to him, "great battle Trip, hard luck you didn't win." But Trip only replied with a nod and "well it's good to know that that Pikachu can use electric attacks – well bad luck for me I guess," and he walked of into the tunnel with out another word.
Ash was interrupted from his daydream by a voice of the intercom saying that in five minutes they will be arriving in Vermilion City. He was glad that he was nearly back in his home region. He had been gone for nearly a year and a half and he missed all of his friends and family there. He slowly sat up and woke his napping friend in the seat next to him. "Hey Pikachu, wake up. We're nearly home!"
"Pikapi?" said the electric mouse Pokémon drowsily. But then he sat up cheerfully.
Ash was extremely exited to go home. But, before returning to Pallet Town he had to go and visit his old friends. As soon as he arrived in Vermilion City he ran to Cerulean City to find Misty. He had missed Misty a lot during his time in Unova. He had taken the time to catch an Alomomola for her as a present. She was happy to see him and was absolutely ecstatic to see the new Pokémon. After spending two days in Cerulean City Ash decided to head down to Pewter City to see how Brock was doing at medical school. Unfortunately Misty could not come with him because her sisters were away again and she had to take care of the Pokémon gym.
On the way to Pewter City Ash couldn't stop thinking of the way Misty had been acting. Even for a girl she had been acting strange. She was always smiling and laughing all of his jokes, even the bad ones that he made on purpose to see if she would laugh. She also always blushed whenever Ash complimented her. But Ash shook of this thought, as he didn't how answer to it. But, he was sure it would come to him eventually.
Ash met Flint, Brock's father, just on the outskirts of Pewter City selling rocks like when the two had first met with the rocks still as expensive as always. Flint said that Brock was currently on school break and was in the Pewter Gym battling the new onslaught of new trainers who had recently gotten their Pokémon from Professor Oak.
Ash arrived at the Gym about 20 minutes later to a large queue that had formed out side. He decided to go around the back to the entrance that was only for Brocks family. When he entered he could hear Brocks commanding voice ordering his Steelix to use dragon breath. After his Steelix finished the move Ash heard the referee declare that Brock was the winner. Then Ash came out from behind the boulder to greet his old friend. Brock, like Misty, was ecstatic to see Ash again after so long. Also like Misty, he was even more exited when Ash gave him a Gigalith that he had found abandoned after the Pokémon League had finished. Brock promised to take good care of the Gigalith to make it even stronger. Ash spent a further 2 days in Pewter City with Brock before leaving for his own Town of Pallet.
Before arriving his hometown he had to pass through Viridian City. Professor Oak had told Ash that the gym leader there had disappeared and was nowhere to be found. With that information, Ash thought that the gym would have become run down. But, before he could finish that thought he heard someone behind him call out "Hey Ashy-boy" only one person ever called him that. He turned around to see his original rival Gary Oak. "What are doing at my gym Ashy-boy?" he said.
"I was just passing through to Pallet when I saw the gym. When did it become your gym anyway?" replied Ash.
"I've been the leader of this gym for about six months now." He then said jokingly "Have you been under a rock for that time Ashy-boy?"
"No Gary. I've been in the Unova region for the past YEAR AND A HALF. I just got back a few days ago."
"Right; I had forgotten you went to the Unova Region. How was it Ashy-boy?"
"It was awesome I caught more cool Pokémon and I was able to win the Pokémon league there"
"The trainers there must be pretty weak if you were able to win the tournament"
"Screw you Gary!"
"I'm just messing with ya, can a take a look at all of your new Pokémon then?"
"Sure thing Gary."
Ash went on to release all of the Pokémon he had on him. His Serperior, Emboar, Samurott, Boldore and Krookodile all came out instantly, still happy that they one the Pokémon League. Pikachu topped it of by jumping off Ash's head to land in front of the rest of the group. "Impressive Ashy-boy, your Pokémon seem to have actually evolved to their final state"
"Well, everyone except Boldore here" Ash said pointing to the Ore Pokémon.
"And why is that?" inquired Gary
"It needs to be traded to evolve, and I couldn't give this guy away even if I wanted to" Ash replied while rubbing the Pokémon fondly.
"Typical Ash" Gary said coolly. "You said you were going to Pallet right?
"Yeah, I'm heading there right now"
"I'll come with you then; I haven't been back there in ages"
"Sure Gary, I was getting it a bit lonely traveling by myself."
Halfway through Route 1 Ash was smashed from behind by what seemed like a very pointy wreaking ball. Ash expected a large thunderbolt from Pikachu but all he heard was Pikachu happily talking to the thing that had hit him. He slowly opened his eyes to see Gary on the floor laughing and a Pidgeot rolling around with Pikachu. It took a few seconds for the dizzy trainer to realise who this Pidgeot was. "PIDGEOT!" Ash exclaimed loudly when he finally recognised the Bird Pokémon. "Aw, I've missed you buddy," he said happily, rubbing the bird. "Sorry I haven't been back to see you since I released you but I've been far away for a long time." But the Pokémon didn't seem to care about his reasoning instead just hugging and chirping its old trainer.
"Did that Fearow ever attack again?" Ash asked. "Pidgeeeeooooo" said the Pokémon nodding its head. "Beat it every time I'm guessing" said Ash jokingly. The bird nodded in pride.
"Sorry to break up the reunion ashy- boy but do you hear music coming from Pallet?" said Gary. "I do actually, wonder what it's for" replied Ash.
"Maybe its for you 'victory' in Unova" Gary said snidely.
"Well you never know, lets go find out," said Ash cheerfully. Then he faced Pidgeot "sorry buddy but I have to go. I'll check back with you soon – I promise." Then the two trainers took off towards Pallet Town to see what was happening leaving the Pidgeot behind them.