One interesting plot could be Ash having to crossdress to infiltrate an all - female Pokémon trainer group in order to gather information about a rare Pokémon they are rumored to be protecting. It adds an element of mystery and humor to the story.
It could be that Ash crossdresses accidentally. Maybe they stumble upon a magical or mysterious place where some strange power causes Ash to transform into a female - like appearance. Serena then has to deal with this new - looking Ash. They have to find a way to reverse the effect while also facing any challenges that come their way during this time, like dealing with Pokemon battles or other trainers who react differently to this new - looking Ash.
Obviously, Ash is the central character as he is the one crossdressing. Pikachu is almost always there too, as Ash's loyal Pokémon partner. Then there could be other trainers like Misty and Brock who might react in different ways to Ash's new look. Some fanfictions might also introduce new characters who play important roles in the story related to Ash's crossdressing situation.
Well, it could start with Serena being initially shocked but then finding it hilarious when Ash crossdresses as her. This shared moment of laughter can bring them closer. They might start to have more open conversations about their dreams and fears. For example, Ash could share his insecurities about always winning battles, and Serena could comfort him in a new, more intimate way because of this unique situation.
In a more elaborate plot, Ash crossdresses as Serena to infiltrate an all - female Pokemon trainer's secret society. Serena coaches him on how to act like her. As he delves deeper into this society, he uncovers a plot that threatens the entire Pokemon world. He then uses his skills and the element of surprise (since no one expects 'Serena' to be so battle - savvy) to save the day.
Brock would be more understanding. He's always been interested in girls, but he also values friendship. So he would probably offer his support to Ash, while also maybe giving some advice on how to act more 'ladylike' if that's what the situation calls for. As for the other Pokemon in Ash's team, they might not fully understand the concept of crossdressing, but they would sense that Ash is still their trainer and would protect him (or her in this case) as usual.
Pikachu is a very likely candidate. It's Ash's most iconic Pokemon and has a deep bond with him. Whenever Ash is in trouble, Pikachu often steps up to protect him.
Ash could be a Pokémon trainer with a different starting point in this fanfiction. Born in 1987, by 1997 he might have already made a name for himself in local Pokémon battles. He could have a team of Pokémon that he rescued from difficult situations, like a Charmander that was abandoned by its trainer. His story could revolve around giving these Pokémon a second chance and proving that Pokémon don't need to be 'perfect' to be strong.
The impact of Ash's loss in the fanfiction could extend beyond just himself. His Pokémon might also feel demoralized. However, this could also be an opportunity for them to grow stronger together. Ash could start training more intensively, seek new training methods, or even try to catch new Pokémon to strengthen his team.
One popular type of Pokemon Ash and Pikachu fanfiction might be adventure - based. For example, Ash and Pikachu could embark on a journey to a new and mysterious region filled with undiscovered Pokemon species. They might face challenges like difficult terrains and powerful, previously - unseen Pokemon. In this fanfiction, Pikachu's electric powers could be enhanced in some unique way, and Ash would have to strategize differently to overcome the obstacles.