One possible scenario in this fanfiction could be that Ash encounters Mewtwo in a new, uncharted region. Mewtwo, being intrigued by Ash's unwavering spirit, decides to test him. Ash passes the tests with the help of his Pikachu and other Pokemon. This leads to Mewtwo seeing Ash as a worthy trainer and allowing itself to be caught. It would be a great twist on the usual Pokemon-catching storylines.
Well, in fanfictions like this, sometimes the story might focus on the emotional aspect of Ash catching Mewtwo. Ash might understand Mewtwo's pain of being created in a lab and feeling alone. He could offer Mewtwo a place where it belongs, among his other Pokemon friends. This emotional connection could be the key factor that makes Mewtwo decide to be caught by Ash.
The plot could involve Ash hearing rumors about Mewtwo's location. He sets out on a journey to find it. Once he does, he tries to communicate with Mewtwo. Mewtwo initially resists but Ash's pure intentions start to sway it.
In many Pokemon fanfictions where Ash catches Machop, it often shows Ash's growth as a trainer. Maybe he discovers Machop in a unique situation, like in a hidden valley. Machop is a strong and determined Pokemon, so when Ash catches it, it could potentially become one of his most powerful allies. It might be a story full of adventure and challenges as Ash tries to train Machop and bond with it.
In many fanfictions where Ash catches Lugia, it often involves a great adventure. Maybe Ash stumbles upon Lugia in a hidden cove. Lugia, being a powerful and majestic Pokémon, would be a huge addition to Ash's team. It could change the dynamic of his battles completely. He might have to prove himself worthy to Lugia first, perhaps by showing his kindness and determination in protecting other Pokémon in the area.
There's a fanfic where Ash catches Mew and Mewtwo during a special tournament. The story focuses on how Ash has to face off against powerful trainers who also have their eyes on Mew and Mewtwo. It's a great read as it shows Ash's growth as a trainer and how he strategizes to keep these two Pokémon safe from those who might misuse their power.
In a Pokemon fanfiction with Ash and Mewtwo, it could start with Ash encountering Mewtwo in an unexpected place. Maybe in a hidden forest where Mewtwo is observing the wild Pokemon. Ash, being his curious self, tries to approach Mewtwo. Mewtwo, initially hostile, realizes Ash's pure intentions and they start an unlikely friendship. This could lead to many adventures where Ash and Mewtwo face various challenges together, like battling against a new, powerful and evil Pokemon organization.
Perhaps Mew and Mewtwo are in a fight against an evil force that threatens the Pokémon world. Ash arrives at the scene and manages to communicate with them. He offers his help and through their combined efforts, they defeat the evil. As a result, Mew and Mewtwo see Ash as a true hero and allow him to catch them, leading to a new chapter in Ash's Pokémon journey.
The relationship can develop through shared experiences. For example, if they get trapped in a strange dimension together. They'll have to rely on each other to find a way out. This mutual dependence can lead to a stronger bond.
Obviously, Ash is one of the main characters. He is the Pokémon trainer on a quest to catch Mewtwo.
Themes can vary widely. However, the concept of trust is often explored. How does Ash gain Mewtwo's trust? It could be through his actions in battles, his respect for Pokémon, or his ability to see Mewtwo not just as a powerful entity but as a being with feelings. Additionally, the theme of the underdog (Ash) facing the seemingly unbeatable (Mewtwo) is quite prevalent. It makes for an exciting narrative as we see Ash use his wits and heart to achieve the seemingly impossible task of catching Mewtwo.
A fanfic could be centered around Ash exploring a new region where Mimikyu is said to be very common. Ash is eager to add a new and different Pokemon to his team. He meets a local trainer who tells him all about Mimikyu's habits. Ash follows the trainer's advice and goes to a particular meadow where Mimikyu likes to play. He waits patiently until he sees a Mimikyu. Ash then uses his best Pokeball and with a little bit of luck, catches Mimikyu. Once caught, he discovers that Mimikyu has some hidden powers that he's excited to explore and train with.