What If Ash was in Pokemon Horizons?

The Ancient Poké Ball!

Amethio and his Corviknight attempt to snatch Liko, only to be stopped by another barrier summoned by her pendant.

Liko gives Ash a knowing smile, telling him she's gonna be okay, Ash smiles back before turning his attention to Team Rocket.

Jessie: So twerp, you gonna let your friend come with us?

James: Or will you finally hand us that Pikachu!

Meowth: You can only choose one!

Wobbuffet: Wobbuffet!

Ash: Neither!

Ash sends out his Pidgeot and she uses Wing Attack to set Roy and Fuecoco free, and a Thunderbolt from Pikachu sends them flying.

Team Rocket: We're blasting off again!

Wobbuffet: Wobbuffet!

Liko then notices Roy's ancient Poke Ball glowing with her pendant. As the barrier comes down, Friede and Charizard try to get to the kids, but Zirc, Onia and their Skarmory's stand in his way using Gust.

Ash is able to stay with Liko and Roy due to being close to them before the Skarmory striked.

Amethio recalls his Corviknight and confronts Liko and Roy himself, sending out his Ceruledge to battle them with.

Liko: I don't think we can take him on, but I'm willing to try!

Roy: Me too!

Ash: Yeah!

Amethio: If you do wish to join this battle Ketchum, you must use your Quaxly.

Ash sees what Amethio is planning, having him use his weakest Pokemon, he remembers when Faba did the same, but it didn't work, and he's confident the same will happen here, so he gives a determined grin and recalls Pidgeot and sends out Quaxly.

The battle starts with Sprigatito and Fuecoco attacking together with Leafage and Ember.

Quaxly fires off a water gun, but it's not very effective.

prigatito, Fuecoco and their trainers attack from different sides, only to have their attacks cut through by Psycho Cut, which lands a hit on both Pokemon.

Quaxly sneaks up behind and lands a pound, it doesn't do much.

Amethio: Just stop this pointless struggle.

Sprigatito and Fuecoco, having taken heavy damage, activate their abilities, Overgrow and Blaze. Sprigatito uses Leafage, and as Ceruledge blocks, Fuecoco comes up the front and lands a hit with Ember.

Quaxly's abilty of Torrent is activated, which Quaxly uses to land a stronger water gun, doing some damage.

Still thinking their teamwork won't change the outcome, Amethio has Ceruledge use Phantom Force, doing heavy damage to both its opponents.

As Ceruledge is ready to deliver the final blow, Liko and Roy's treasures start glowing together again. Roy's Poke Ball opens up, and from it a beam of light splits the clouds above. To everyone's surprise, a black Rayquaza comes down from the sky.

Ash: That's Rayquaza....

Roy: I thought the Pokeball was empty.

Liko scans it with her Rotom Phone. Friede joins up with Ash, Liko and Roy as the Rayquaza uses Draco Meteor, hitting the entire beach and forcing the Explorers to retreat.

Roy tries to get Rayquaza back in the Poke Ball, but it refuses, glances at Liko for a second and ascends into the sky. Liko breathes a sigh of relief, and Roy falls to the ground, happy that it left.

At Roy's house, Liko and Roy are excited that they actually saw a legendary Pokemon.

Roy: Wait Ash, didn't you know it's name, that means you saw one before right?

Ash: Yep, though it's usually green, I did encounter a black Rayquaza back when I was in Kalos .

Liko: Wow...

Roy's Grandpa acknowledges that black Rayquaza that was once under ownership of the ancient adventurer.

Friede: But why would a Pokemon like that be in Roy's Poke Ball?

But the elder honestly has no idea. When he was young, the elder found that Poke Ball on the beach to give to his grandson not knowing there was actually a Pokemon inside.

Roy is thrilled to know that his ancient Poke Ball belongs to the adventurer of legend.

Thinking Roy's Poke Ball has some kind of connection to her pendant, Liko asks the elder about it, but he doesn't know the answer.

Likewise, Friede is interested in this mystery too, wanting to look more into it as a Pokemon professor.

Ash is also interested in the mystery, wanting to befriend Rayquaza.

Friede gets a call from Mollie saying that she's all done treating Ash, Liko and Roy's Pokemon.

Fuecoco looks at the Oran Berries Roy wanted to give him, and Charizard gives Fuecoco a Poke Ball.

Roy arrives at the Brave Asagi and tells Fuecoco how he really feels before Fuecoco, Quaxly and Sprigatito come out.

As Sprigatito jumps into Liko's arms, and Quaxly goes atop Ash's head, Fuecoco approaches Roy and spits out a Poke Ball, having decided to become his partner. Roy then catches Fuecoco and Ash and Liko are amazed that they was there to witness it.

Ash: Roy, now that you have a Pokemon, you should join us!

Liko: Yeah!

Pikachu: Pika Pika!

Roy: I don't know if my grandpa will let me.

Unexpectedly, Roy's grandpa has been listening, and ultimately accepts his grandson's decision to go with the Rising Volt Tacklers on adventures.

As the Rising Volt Tacklers prepare to set sail for Paldea, Roy gives Friede the flag for their ship that he found when it washed ashore. Roy then comes to think of Fuecoco as his greatest treasure that washed ashore. The Brave Asagi prepares to depart from the island as its people, with Roy's grandpa, wish Roy safe travels.

As our trio of heros gaze at the sunset, Roy vows to find Rayquaza, as does Liko, Ash too, prompting the three to share a laugh as the Brave Asagi flies into the sunset.

Ash: Paldea! Here we come!