Perhaps in this new region, Ash discovers a powerful new Pokemon that others want to control. His friends, fearing the power of this Pokemon, betray him to protect the region. They might think that Ash is being too reckless with this new discovery and that it could lead to destruction. It could also be that there's a prophecy in the new region that Ash is somehow involved in, and his friends misinterpret it and believe he's the cause of potential harm.
Another plotline could be that the new region has its own set of rules and values that Ash unknowingly violates. His friends, being more in tune with the local ways, feel that they have to side against him. This could lead to a situation where Ash has to prove himself all over again, not only to his friends but also to the people and Pokemon of the new region.
In such a fanfiction, the plot could involve Ash being betrayed by his long - time friends. Maybe they envy his success in the Pokemon world. For example, Gary could spread false rumors about Ash in the new region, causing the local trainers to distrust Ash. This would make Ash's journey in the new region much more difficult as he has to not only deal with new Pokemon and challenges but also regain his reputation.
It could be his rivals. For instance, Tracey or Paul might see Ash's potential in the new region as a threat and decide to betray him. They could try to sabotage his battles by giving false tips to his opponents or stealing his battle strategies.
One possible plotline could be that Ash's new friends in Galar turn on him due to some misunderstanding. Maybe they think he's trying to steal the spotlight in Pokemon battles. For example, if Ash wins a big tournament that some local trainers had high hopes for. Another could be that a villain in Galar manages to manipulate those around Ash into believing he's a threat to the Galar region. This could be by spreading false rumors about his intentions with powerful Pokemon. Or perhaps there's a new type of Pokemon in Galar that has some sort of mind - controlling ability and it's used on Ash's friends to make them betray him.
One possible plotline could be that Ash and Cynthia are betrayed by a powerful and long - hidden organization in the Pokemon world. Maybe they are lured into a trap under false pretenses. For example, they are told there is a great Pokemon discovery but it's actually a setup to steal their Pokemon or get some important information from them. Another could be a betrayal from a so - called friend. This friend might be jealous of their achievements and decides to side with an enemy to bring them down. This could lead to Ash and Cynthia losing battles they should have won and facing challenges that seem insurmountable at first.
One possible plotline could be that Ash is betrayed by his so - called friends in the Pokémon world. They might spread false rumors about him, making everyone turn against him. Meanwhile, Mewtwo, who has formed an unlikely bond with Ash, is also betrayed by the scientists who created it again. They try to recapture Mewtwo to use it for their evil experiments. Ash and Mewtwo then team up to fight against their betrayers and prove their worth.
One possible plotline could be that her so - called friends in the Pokemon journey turn against her for some reason, like jealousy over her Pokemon's strength. Maybe they try to steal her Pokemon or spread false rumors about her to isolate her.
Ash would probably be really hurt at first. He's always been so trusting of his friends. He might go off on his own for a while to clear his head, like he did when he had a falling - out with some of his friends in the past.
Betrayal could also stem from a misunderstanding. Maybe Ash or Cynthia accidentally offend someone without realizing it. For example, they might unknowingly step on a trainer's dreams or beliefs. And that trainer, feeling deeply hurt, decides to betray them. Or it could be that a Pokemon they both have a connection with has a different loyalty that they were not aware of, which leads to the Pokemon causing their betrayal.
One possible plotline could be that Ash discovers May has been secretly working with a rival trainer in order to gain an advantage in a big tournament. This would make Ash feel betrayed as he thought they were friends and training partners. Another could be that May betrays Ash for a rare Pokémon that Ash was also after, choosing the Pokémon over their friendship.
One possible plotline could be that Ash's friends start believing false rumors about him being a traitor to their group. For example, an enemy might spread lies that Ash is secretly working for a rival organization. So, his friends gradually turn their backs on him, leaving him alone and confused. He then has to prove his innocence while also dealing with the pain of betrayal.