The story may develop with the village realizing she's missing and sending out search parties. Some characters might be sympathetic to her situation and try to help her secretly. Meanwhile, she has to deal with the physical and emotional challenges of pregnancy alone. After the baby is born, she may start training the baby in secret ninja skills while trying to keep their existence hidden from the world that might want to use or harm them.
Often, the trainer will go on a search for Pikachu. They might explore different areas, ask other Pokemon or trainers if they have seen Pikachu. This search can lead to all kinds of adventures and encounters with new Pokemon.
He might first find a place to hide, like an abandoned building. There, he starts to realize how difficult it is to be on his own. He has to find food and water by himself.
Well, he could meet new friends or allies who help him grow stronger. For instance, he might encounter a group of outcasts who understand his situation and teach him new skills or ways of thinking.
Maybe he's running away from the pressure in the village. There are always high expectations on him, and he might feel suffocated and need some time alone to figure things out.
The remaining members of Team 7 could struggle without him at first. They might have to re - evaluate their own skills and teamwork. Eventually, they could either try to convince Naruto to come back or move forward and become stronger on their own.
Often, his friends in Konoha will start to search for him. They might split into teams and scour the surrounding areas. For example, Sasuke could use his Sharingan to look for any signs of Naruto's departure. Meanwhile, back in Konoha, there could be unrest as the villagers start to worry about the safety of the village without Naruto.
It could be that Naruto discovers something about the nature of his pregnancy that scares him. For example, he might find out that the child has some sort of special power that could put it in danger. So he runs away to figure out how to handle the situation without endangering the village or the child. He might seek out a hermit or an old sage to get advice on what to do.
Often, the storyline starts with the shock of the pregnancy. Naruto might be initially confused but then quickly becomes supportive. The story then usually focuses on their preparation for the baby, like finding a safe place to live.
At first, Itachi might be a bit distant, but as they run away and are forced to rely on each other, a deeper connection forms. Naruto's positive attitude would gradually break down Itachi's walls. They could start sharing their hopes and fears. Itachi might open up about his family and his regrets, and Naruto would listen and offer his own perspective. This sharing would strengthen their bond, and they would become like brothers, protecting and supporting each other.
It could be her best friend. In many stories, best friends have a special bond and can sense when something is wrong. So, her best friend might start looking for her and be the first to find her.