With a fierce determination burning in his eyes, the young trainer in the blue T-shirt bellowed at the top of his lungs, "FULL POWER!" The yellow electric mouse, Pikachu, stood at the ready, enveloped in a brilliant yellow ball of electricity as it prepared to unleash a devastating jolt of high voltage onto the Island Guardian of Melemele Island, Tapu Koko. Ash Ketchum, hailing from Pallet town, had been pursuing this dream since he was but a mere ten-year-old, and now, it seemed, it was finally within his grasp.

In a grand mansion located in the distant Hoenn region, a young girl smiled as she watched the events unfold on television. She clutched at the blue ribbon that had been gifted to her, and a frog-like, bipedal, meditating Pokémon opened its eyes, sensing the momentous occasion.

Three days later, Ash Ketchum, now the proud champion of the Alola region, strode through the lush forests of Kanto, returning home with the champion's trophy held firmly in his grasp. As he reached Viridian City, he caught sight of a bright white and blue Pokémon soaring through the skies overhead. The mysterious creature seemed to take notice of Ash before disappearing into the distance. Ash turned to his trusty companion Pikachu and gazed up into the sky.

"Weird, isn't it buddy? We first started our journey seeing Ho-Oh, and now it's Lugia. Both of them are legendary Pokémon said to roam the skies of the Johto region. Maybe this is the start of something new," Ash exclaimed, his fist clenched in excitement as he set off on his next adventure.

Three days later, Ash woke up in high spirits and bounded down the stairs. He cast a glance at his Kalos outfit, which his mother had so carefully prepared for him, and then at the five Pokéballs lying on the table. As he reached for the door to greet his friend Brock, there came a knock.

"So we're doing it again, huh buddy?" Brock said with a grin as he looked at Ash. It had been some time since the two had set off on a journey together, but all of their previous excursions had been confined to a single region. This time, however, was different. They were embarking on a grand trip around the globe.

"You bet!" Ash exclaimed, his traditional goofy smile spreading across his face. "I can't wait to see what new adventures and challenges await us!"

Ash and Brock shared a hearty breakfast at the Ketchum residence before setting off on their journey. As they were about to leave, Professor Oak arrived to speak with Ash and presented him with a new Pokédex, known as the International Dex. Ash looked at the five Pokéballs and then at Pikachu, "Alright, let's do this guys!" he chuckled, ready for whatever the world had in store for them.

: A few days later :

"Pikachu! Electro Ball!" Ash cried out, his voice filled with fierce determination as Pikachu unleashed its final attack upon the Mega Gyrados of Champion Lance, Champion of both the Kanto and Johto regions. With a deafening crash, the Mega Gyrados was defeated, turning back into its normal form as it fainted on the battlefield. Pikachu stood victorious, barely able to stand as it smirked in triumph.

"And there we have it! The new Champion of the Kanto and Johto regions, Ash Ketchum from Pallet Town!" the referee declared, as familiar faces watched on in awe from the stands. Ash had taken one step closer to achieving his ultimate goal.

After this victory, Ash and Brock travelled to the Hoenn region, where Ash aimed to win the region and meet Serena. However, they did not cross paths. Ash went on to defeat the Champions of Hoenn, Sinnoh, and Unova, but before he could proceed to the Kalos region, he received a call for duty as an Ultra Guardian. Due to this, Ash and Brock parted ways in Unova, with Brock returning home to retake the title of Pewter City Gym leader and Ash joining the Ultra Guardians.