What If Ash was in Pokemon Horizons?

The SOS is from Tandemaus?

One the way to Paldea, a storm forces the Brave Olivine to make a landing. After the storm, Ash, Friede and Roy notice that the flag has been damaged. Mollie also requests Pokémon check-ups since it will be a while before they get off the ground.

After Mollie finishes with Snorunt, Liko comes in requesting a check-up for Hatenna. It has been feeling off because of the storm; one just like the one from when she and her trainer first met. Chansey gets a fluffy white towel for Hatenna. Liko notices that Hatenna has taken a liking to Chansey. Friede's Charizard, Slugma and Carkol, Ash's pokemon and Ash come in, all exhausted from having worked so hard in the engine room during that storm. Liko tends to Charizard, who instantly perks back up once it has one of Chansey's eggs. Next, Shuckle comes in, and Hatenna trembles a bit. After Mollie gets a tiny thorn out of its hind leg, Chansey takes the lingering pain away with Heal Pulse. Hatenna seems elated by this move, wanting to learn how to use it too. Suddenly, she runs out and point Ash, Liko and Mollie to an injured Tandemaus. Looking up the Pokémon on her Pokédex, Liko thinks there should be another since they are usually seen in pairs that never split up. Mollie believes this could be an emergency. Liko notices something troubling Hatenna, and Mollie thinks that she's taking in Tandemaus's feelings. Mollie decides to let it rest in the infirmary and make finding the other one their top priority. However, Tandemaus jumps out of Chansey's arms and has the group follow it into the forest.

They arrive at a cave with a fallen tree blocking it. The Tandemaus calls into it, making Liko realize that its partner is in there. They try to push the tree, but it's too heavy. Liko decides to widen the gap at the bottom, having Sprigatito dig with Tandemaus. While Mollie isn't able to fit through the gap, Liko volunteers.

Ash: I'll go with you!

The two enter the gap

Entering the cave, it isn't long before Ash and Liko find Tandemaus's partner, handing it over to Mollie. Liko hears Tandemaus crying into the cave again, realizing there may in fact be more in there. She also lets Hatenna wait outside knowing this may be too much for her. Liko tells Mollie and Ash that Tandemaus may have more friends trapped in the cave, and despite Mollie's protest, Liko ventures in anyway.

Ash: Don't worry Mollie! I'll go after her!

Ash runs after Liko

Hatenna, feeling worried about Liko, asks for Chansey's help. Chansey gives the Calm Pokémon one of its eggs, and Mollie gives her a fluffy white towel to carry it into the cave.

Ash and Liko come to a branching pathway, getting confused as to which way to go. Liko gets even more worried when Tandemaus suddenly collapses from exhaustion.

Ash picks up the Pokemon

Ash: We should hurry, if there are more then they're proably like this one...

Outside the cave, Mollie has gotten the entire crew to help get Ash and Liko out of the cave. They tie a rope to the tree and all pull together to move it out of the way. Mollie calls to them, but hears Liko's voice from a hole off to the side, filled with relief that they and the Pokémon are okay as she throws her arms around Liko. Liko reveals that the Tandemaus helped her escape by gnawing through the rock. She also shares that Hatenna learned Heal Pulse. Mollie praises the Calm Pokémon, who suddenly falls back from exhaustion.

Back on the ship, Mollie, Hatenna and Chansey chase Maushold (who made their new home on the ship) around the infirmary. Liko looks up Maushold on her Pokédex, revealing that was the Pokémon they saved, not Tandemaus. Mollie was so focused on treating the patient she already had that she hadn't even considered that possibility.

Liko: And it was all thanks to Hatenna!

Ash: Yep! Great job Hatenna!

Maushold runs out with Hatenna and Chansey still giving chase.

I know the chapter didn't provide much, but man it feels good to be back :)