One possible plotline could be Naruto and Sakura being on a mission together and in a moment of danger, they accidentally confess their secret love for each other. Another could be that they keep their relationship a secret from their friends for a long time, but little things keep giving it away, like stolen glances and blushes.
Another plotline could involve the family going on a journey to discover a long - lost ninja technique that has been in Naruto's family for generations but was lost. Along the way, they face various enemies and also bond as a family. Sakura uses her medical ninjutsu skills to keep everyone healthy during the journey.
In some fanfictions, there could be a plot where an old enemy resurfaces and targets their family. This forces Naruto and Sakura to work together not only to protect each other but also their new life together. It could also explore how their relationship has changed since they got married, like Naruto becoming more understanding of Sakura's need for independence in her career as a medic.
In some fanfictions, their secret relationship could start during their time as teammates. Maybe they start to have feelings for each other during a difficult mission but keep it a secret to avoid any distractions or interference from others, especially Naruto who might not understand at first. They could communicate through hidden glances and small gestures that only they understand.
One interesting plotline could be exploring how they first fell in love. Maybe it was during a training session where Naruto showed his determination and Kushina was drawn to that. Another could be them facing challenges together, like dealing with the village's disapproval of their relationship at first.
Another plotline could be them going on a mission together as young ninjas. They face challenges and have to rely on each other. Maybe they get lost in a forest during a mission and have to use their respective ninja skills to find their way back. Along the way, they share stories and secrets, strengthening their bond as friends and comrades. This shows how they grow together in the ninja world.
Another plotline could involve a secret jounin who is actually a spy from another village but develops a loyalty to Konoha. They would be in a constant struggle between their original mission and their newfound feelings for the village. This could lead to many internal conflicts and interesting character development as they try to keep their true identity hidden while also trying to protect Konoha from threats they know about from their own village.
One interesting plotline could be a character discovering a new and unique secret power that changes the course of a battle. For example, Naruto might find a hidden power within himself that allows him to control time briefly, enabling him to outmaneuver his opponents in a crucial fight.
One interesting plotline could be about a secret society within the Naruto world that is dedicated to protecting an ancient and powerful jutsu. They operate in the shadows, and the main characters gradually discover their existence and have to decide whether to join or oppose them.
There could be a plotline where Naruto and Sakura discover a hidden part of the academy that holds ancient ninja secrets. They have to work together to unlock the secrets, and along the way, they face various challenges and also grow closer as friends. This could also lead to them learning new powers or techniques that are unique to this hidden part of the academy.
One interesting plotline could be Naruto, now in Sakura's body, using his unique combat knowledge to improve Sakura's fighting skills in a new and unexpected way. For example, he might combine his shadow clone technique with Sakura's brute strength, creating a whole new fighting style.