Perhaps Naruto is trying to protect Ino in a really extreme way. He could think that there are threats to her life that no one else is aware of. So, instead of talking to her or her friends about it, he decides to take matters into his own hands and kidnaps her to keep her safe in a secret location. But this would obviously cause a lot of chaos among the other characters in the Naruto universe.
One possibility could be that Minato was under some kind of mind - control spell. Maybe an enemy of Konoha managed to manipulate him into thinking that Naruto was in danger by being in the village. So, Minato kidnaps Naruto to take him to what he believes is a safer place. But as the story unfolds, Naruto tries to figure out what's wrong with his father and tries to break the spell on him.
One possible plot could be that Tsunade kidnaps Naruto because she believes an enemy is after him and she wants to keep him safe in a secret location. She might think that by taking him away from the village, she can train him without any distractions or threats.
Well, it could be that Anko has some secret motive. Maybe she's being controlled by an enemy force who wants to use Naruto for some dark purpose. So she kidnaps Naruto to deliver him to this force.
Maybe in the fanfiction, Kushina kidnaps Naruto because she believes she can protect him better away from the Hidden Leaf Village. She thinks the village has become too dangerous for him. However, Naruto doesn't understand her intentions at first and struggles against her. As the story progresses, he realizes her love and the real reason behind her actions.
The plot could involve Ino being in a situation where she needs to understand the Sharingan to save a friend. For instance, if her friend was under the control of an enemy who had a Sharingan - based mind control. Ino would then seek out someone with knowledge of the Sharingan, like Kakashi. Together, they would try to break the mind control and in the process, Ino would learn a great deal about the Sharingan's capabilities.
It could also be part of a more complex plot where Naruto has made a promise to protect Ino at all costs. There might be a prophecy or some sort of dark force threatening the village and Ino is specifically targeted. Naruto, knowing the importance of her life for the village or for some other deeper reason, gives up his own life to ensure her safety. This could lead to a great deal of character development for the other characters as they deal with Naruto's sacrifice.
One possible plot could be that Naruto and Ino accidentally end up in a situation where Ino discovers she's pregnant. They then have to face the reactions of their friends and family in the Hidden Leaf Village. Naruto might be initially shocked but then quickly step up to support Ino.
Well, in such a fanfiction, the plot might involve Naruto using his charm and clumsy yet endearing ways to flirt with Ino. Maybe he starts by complimenting her flower arrangements in a really cheesy way. For example, he could say something like 'Ino, your flowers are as beautiful as you are.' And then Ino might blush and playfully push him away at first but gradually warm up to his flirting.
Well, it could be that they betray their village. Maybe they are tricked into believing false information about Konoha being corrupt. So they side with an enemy force, thinking they are doing the right thing.
A simple plot could be that Ino cuts her hair on a whim. Naruto is the first one to notice. He comments on how different she looks. This makes Ino self - conscious at first, but then she realizes that Naruto's comments are more of admiration. As the story unfolds, they end up going on a small adventure together where Ino's new haircut becomes an advantage in some situations, like when they need to blend in or move quickly without her long hair getting in the way.