What If Ash was in Pokemon Horizons?

Reunion at the Ancient Castle!

Following their adventure in the Galar Mine, Liko, Ash, Roy, and Friede have returned to the Brave Asagi with the mysterious Pokémon that emerged from Liko's pendant. With none of the Rising Volt Tacklers or even the Pokédex recognizing it, Liko, Roy, and Friede head out to ask more from Liko's grandmother. Friede also asks Captain Pikachu to watch over the airship while they're gone.

Liko, Ash, Roy, and Friede arrive in the Wild Area

Ash: Wow! Glad to be back!

Liko's grandmother's Squawkabilly approaches them

Squawkbilly: Liko! Old castle!

Ash: Who's that Pokemon?

Rotom: Squawkabilly, the Parrot Pokemon, a normal and flying type, These Pokémon prefer to live in cities. They form flocks based on the color of their feathers, and they fight over territory.

Roy: I think it wants us to follow it.

the group to follow it. Squawkabilly eventually leads them to what looks like a wall of stone, until a Stonjourner moves aside to reveal a secret passage for them. They go inside and Stonjourner moves back to cover the entrance again,

The group walk down the passage.

Liko: I never really saw my grandma other than brief visits, and I don't even count those as actual meetings, the last time I saw her was a year before I went to Indigo academy, and that;s when I got the pendant...

Ash: Family member who you barely see? Been there before...

Eventually, the Rising Volt Tacklers group arrives at the old castle they were searching for.

Liko: Grandma?

The group is right away greeted by Liko's grandmother's Arcanine and then her grandmother, Diana, herself.

Diana: Well I'll be, the World Monarch in the same room as my granddaughter.

Ash: Heh, nice to meet ya!

Roy and Friede introduce themselves to Diana, while Liko introduces her to her partner Pokémon, Sprigatito. Diana shows them around the castle, which serves as one of her hideouts and as a spot where wild Pokémon can come and go as they please. Sitting down to talk, Diana reveals that she too had been targeted by the people after her pendant and thanks Liko for keeping it safe. Liko and Friede struggle to explain the situation, but before they can properly do so, the truth reveals itself when the mysterious Pokemon climbs out of Liko's bag and moves towards a surprised Diana. Liko explains that her pendant transformed into this Pokémon, which Diana identifies as Terapagos.

Ash: Terapagos? Do you know more about it?

While she knows the Pokémon's name, she hadn't expected the pendant to be a hibernating Terapagos, even if its form differs from the recorded form with a big shell. She also suspects that Terapagos used to be one of Lucius' partners, much to Liko and Friede's surprise.

the group eats a meal of canned food and follows it with cups of tea. Liko asks Diana to tell her how she became an adventurer, which she's happy to tell now that Liko has taken her own first step into the world. When she was even younger than Liko is now, she had discovered an old briefcase in her attic. Inside it, she had discovered the pendant and a book written by Lucius about his adventures. This inspired her to start her own journey to learn more about Lucius, but no matter how hard she searched, she never found a single sign of him. 30 years ago, she finally gave up on her search, but still keeps on adventuring, all thanks to the inspiration provided by Lucius. Several months ago, an old friend of hers offered to support her on her adventures, but when it turned out that said friend was associated with a shady organization that was after her pendant, she chose to hire the Rising Volt Tacklers to protect both Liko and the pendant. She thanks Friede for protecting her granddaughter.

Diana: And The World Monarch protecting her will also help me sleep at night, thank you for that dear.

Ash: It was my pleasure miss, anything for my friends!

Roy shows Diana the Ancient Poké Ball which the Black Rayquaza had emerged from. Liko also recounts how some mysterious visions had appeared during their encounters with Arboliva and Galarian Moltres, which she now suspects were actually Terapagos's memories. When she asks her grandmother if she knows what "Rakua" is, Terapagos suddenly lets out an excited cry and moves towards a nearby door. Diana answers that Rakua is the name of the paradise that Lucius sought and leaves to fetch something she wants to show them: Lucius's memoirs.

However, whilst Diana is on her way to retrieve the memoirs, her Arcanine and a Blipbug appear behind a window to warn her that intruders are approaching. Moments later, Amethio, Zirc, and Onia enter the building. Friede sends out his Charizard, while Amethio calls out Ceruledge, and Zirc and Onia cover Liko and Roy's escape routes. Terapagos notices Amethio and pulls itself free from Liko's grasp, locking eyes with him and letting out a sharp cry.

The roof bursts open and Team Rocket lands

Jessie: Surpise!

James: Why what do we have there, three acient Poke balls, a Pikachu and a new pokemon to take!

Meowth: Now give em here!

Wobbuffet: Wobbuffet!