A possible plotline is that the tail plug was a cursed object that was placed on Kushina by an enemy long ago. Naruto discovers this and tries to break the curse. He goes on a journey to find a way to remove the tail plug and free his mother from its negative effects, all while facing various challenges and enemies along the way.
It could be a story that combines elements of their family bond. Perhaps the tail plug is an ancient Uzumaki clan relic. Naruto discovers it and it has some connection to Kushina. It could show how they interact with this strange object, with Naruto being curious and Kushina having memories or knowledge about it from her past in the Uzumaki clan.
Perhaps there could be a plot where the tail plug is a key to unlocking an ancient prophecy. Sakura is the chosen one to wield it, and with Naruto's help, they must face various challenges and enemies who also want to get their hands on the tail plug for their own evil purposes.
One possible plotline could be that Naruto is an orphan found by a different ninja clan. He grows up with different values and skills, and his path crosses with Kushina in a completely non - family - related way. For example, they could meet as rivals in a ninja tournament. Another plotline might involve Naruto being from another village entirely and coming to Konoha on a mission where he teams up with Kushina to fight a common enemy. They then form a bond based on mutual respect and shared experiences rather than a family connection.
One plotline could be that Naruto discovers a hidden power within himself that is linked to Kushina's Uzumaki heritage. This power makes him godlike, and he has to learn to control it while also dealing with the memories and emotions related to Kushina that come with it.
Another plotline could involve the Shinigami within Naruto having some sort of mission related to Kushina. The Shinigami might need Naruto to help Kushina fulfill an unfinished task. As Naruto and Kushina work together, they also get to bond on a deeper level, with Naruto learning more about his mother's past and her love for the village and his father.
One possible plotline could be that Naruto is influenced by some dark force and turns 'evil'. Kushina, having come back to life somehow, tries to understand what has happened to her son. She then embarks on a journey to find a way to reverse the effects, leading to a series of adventures where they interact in different ways, like Kushina trying to jog Naruto's memories of their family bond.
One possible plotline could be Naruto's struggle with abandonment issues. Since Kushina left, Naruto might have a harder time finding his place in the village. He could become more withdrawn and have to fight even harder to prove himself. Another could be the search for Kushina. Naruto might embark on a journey to find out why she left and try to bring her back.
One possible plotline could be that Kushina is somehow mind - controlled or influenced by an evil force to harm Naruto. Maybe she's under a powerful genjutsu that makes her see Naruto as a threat to the village instead of her son.
A plotline could be that Naruto has to keep his true parentage a secret for a long time. This secrecy adds to his internal conflict as he tries to fit in with the other ninjas. As the son of Kyuubi and Kushina, he may be hunted by certain groups who want to either use his power or destroy it. He then has to go on a quest to find out more about his parents and his own identity, all while fending off these threats.
A plotline might involve Naruto traveling back in time and meeting Kushina when she was young. They could start as friends and gradually fall in love. Or perhaps there's a prophecy that links them together, and they have to fulfill it, which leads to their mating. There could also be a situation where a powerful enemy forces them to work closely together, and that closeness turns into a deeper relationship.