Perhaps it's about a character who discovers secrets about their dad's past in the Naruto world. They find out about hidden missions, unfulfilled dreams, or old rivalries. And as they learn more, they are inspired to take on their dad's legacy. They might start to train with people who knew their dad, learn his techniques from them, and use those skills to make their own mark in the ninja world.
The plot might involve the main character in the fanfiction facing challenges similar to those their dad faced. It could be about dealing with powerful enemies or making tough moral choices. Say their dad had to choose between loyalty to the village and a personal friendship once. Now the character is in a similar situation and has to decide how to act, all while trying to live up to their dad's reputation.
It could be Naruto's son, if we're thinking in the context of Naruto having a family in the future. He might want to be as great a ninja as his dad and follow in his footsteps.
In this fanfiction, she might learn a lot of cool jutsu from them. Maybe they'll share stories about her dad that she's never heard before.
One possible plot could be that Naruto discovers a strange power within him that makes him sing in a way that can calm the inner demons of the people around him. For example, he might use this newfound ability during a battle to soothe the anger and hatred in his enemies, turning them into allies.
Perhaps Naruto comes to your house seeking refuge from some powerful enemy in his world. While in your house, he shares his stories of Konoha, his friends like Sasuke and Sakura, and his training with Jiraiya. He could also teach you about chakra control and how to perform basic ninja techniques, all while trying to stay hidden from the threat that chased him into your world.
It could be a vengeful spirit. Maybe someone who had a bad experience during Christmas in the past and now haunts the place, leaving those footsteps as a sign of their presence.
One possible plot could be that Naruto, feeling a bit out of place in the Hidden Leaf after a long and difficult mission. He starts singing 'Welcome to My Life' as a way to express his inner turmoil and the challenges he has faced. His friends hear him and it leads to a deeper understanding among them.
One possible plot could be that Naruto, with his godlike powers, accidentally ends up in the My Little Pony world. He then uses his powers to help the ponies against some kind of threat, like a powerful dark magic that the ponies can't handle on their own.
One possible plot could be that Naruto befriends someone whose dad is a rockstar. The rockstar dad could be on tour in the Ninja world. Naruto might get inspired by the rockstar's charisma and use it in his own way to bring people together, like how he does with his ninja friends. He could also learn about a different kind of 'teamwork' from seeing how the rockstar and his bandmates interact.
It could symbolize mystery. Maybe there is someone or something following in the story that is not yet revealed, adding an element of suspense.
Perhaps the fanfiction focuses on a training arc where a Naruto character decides to master the art of swordsmanship. They start with the mindset of 'I am the bone of my sword', meaning they want to be completely in tune with their weapon. During this training, they encounter various challenges, both physical and mental. They might have to face off against a master swordsman from another village who challenges their beliefs and techniques, forcing them to grow and adapt in order to succeed.