The plot might involve a time - travel aspect. Naruto travels back in time and gives Kushina the Gura Gura no Mi. Kushina then has to quickly learn to control this new power while also dealing with her pregnancy. She could use the power to change the future for the better, perhaps preventing some of the tragedies that occur in the Naruto story, like the destruction of the Uzumaki clan.
One possible plot could be that Kushina somehow gains the powers of the Gura Gura no Mi. She could use it to protect Naruto from various threats in the Naruto universe. Maybe she could create powerful shockwaves to fend off enemies like the Akatsuki. Naruto, seeing his mother's new power, would be inspired to train harder and learn how to combine his own jutsu with the power of the Gura Gura no Mi.
In this fanfiction, the Gura Gura no Mi could be a cursed fruit in the Naruto world. Naruto and Kushina have to find a way to break the curse associated with it. They go on a journey together, facing many challenges along the way. Kushina uses her Uzumaki chakra control along with the power of the Gura Gura no Mi, and Naruto uses his Sage Mode and Rasengan techniques to overcome the obstacles in their path.
In this fanfiction, Naruto with the Gura Gura Fruit might face a new type of antagonist. This antagonist could be someone who is also after the power of the fruit or someone who has a power that can counteract Naruto's new abilities. Naruto would have to figure out how to use the Gura Gura Fruit in combination with his existing ninja skills, like his shadow clones. He could create clones and then use the fruit's power through them to launch multiple attacks simultaneously, which would be a very interesting development in the story.
Their relationship could become stronger. Kushina, with the Gura Gura no Mi, would be an even more powerful protector. Naruto would look up to her even more, and they would bond over the new power she has. He might ask her for training tips on how to use such a powerful ability.
One possible plot could be Naruto somehow obtaining the Gura Gura Fruit. He then has to learn to control its powers while still maintaining his own ninja skills. For example, he might accidentally cause earthquakes during battles at first, but as he masters it, he combines the fruit's power with his Rasengan, creating a super - powerful attack.
In a fanfiction about Naruto, the Gura Gura Fruit, and the Third Shinobi War, perhaps the Gura Gura Fruit is a new, mysterious element introduced into the war. Naruto, being the curious and adventurous ninja he is, might be the first to discover it. His friends and allies could be initially wary of this strange power, but as Naruto learns to control it, they see its potential in turning the tide of the war against powerful enemies such as Orochimaru or the Hidden Stone Village's forces.
Naruto could use the Gura Gura Fruit to create huge tidal waves in battles near water sources. This would be a great advantage against enemies not used to fighting in water. For example, if facing the Sand Village ninjas, he could flood the desert battlefield, disrupting their attacks and movements.
Naruto would become more powerful, and this might make him a bit more cautious. He's used to his regular ninja abilities, but the gura gura fruit's power is on a different level. He might be more hesitant in battles at first, not wanting to accidentally cause too much destruction with the fruit's earthquake - causing ability.
His self - confidence might change. On one hand, having this new powerful ability from the Gura Gura Fruit would boost his confidence. But on the other hand, he would also realize that he has a huge responsibility with these powers. He might become more introspective, thinking about how to use the power for good and not let it corrupt him, like how he was always careful with the power of the Nine - Tails inside him.
Maybe in the fanfiction, Kushina takes Naruto to Uzu to protect him from some threat in Konoha. Along the way, they encounter various challenges and Naruto gets to learn more about his mother's skills and strength. Kushina could teach him some Uzumaki - specific jutsu during their travels, which Naruto then uses to fend off enemies later on.
Well, it could be that Dark Naruto, after being abandoned, is found by an outcast group. They take him in and teach him their own values which are different from the village's. He grows up with a different perspective and starts to question the whole idea of the ninja world. Eventually, he might try to create his own 'utopia' in his mind, which could involve overthrowing the current system. But at the same time, he still has that internal conflict of his Uzumaki heritage and what Kushina's abandonment means.
One possible plot could be that they have to face challenges together in a post - war Konoha. They might work on rebuilding the village while also dealing with their new family life. Naruto, with his experience and Kushina's strong will, could make a great team in leading the village in a new direction.