Well, perhaps in this fanfiction, Naruto left because he felt unappreciated in the Leaf. But then the Leaf discovers some secrets or powers that are tied to Naruto. They start to see all the good he has done in the past and make a big effort to bring him back. They might hold a big ceremony to welcome him and show how much they truly value him now.
Obviously Naruto would be one of the main characters as the story is about getting him back. Sakura could also be a main character. She might be one of the ones leading the effort to bring Naruto back, using her medical skills and her friendship with Naruto as reasons to convince him.
Well, it could be about Ino being desperate to have Naruto return to the village or to her life in some way. Maybe Naruto has gone on a long journey or mission, and Ino misses him a great deal. She might take various actions to bring him back, like trying to convince others to go after him or using her own skills to find him.
Well, in some fanfictions, Minato might use his powerful jutsu to break through the barriers between the living and the dead and directly reach Naruto. He could also try to influence the people around Naruto to bring him closer to where Minato is, like using his spirit to communicate with Naruto's friends and convince them to help.
Well, perhaps in this fanfiction, Naruto has been kidnapped by an unknown enemy. Anko, having a soft spot for Naruto, uses her skills and connections to track him down. She might have to face off against other powerful foes who are also after Naruto for their own reasons. The story could involve her teaming up with some of Naruto's old friends, like Shikamaru or Sakura, to rescue him and bring him back to Konoha.
Naruto's reaction could be complex. On one hand, he would be extremely excited. But on the other hand, he would be worried about the consequences. He has learned about the balance of the ninja world and might be afraid that bringing Kushina back could have negative impacts. However, his love for his mother would probably overpower those concerns in the end, and he would still strive to make her return a reality.
One reason could be that Minato has some unfinished business with Naruto. Maybe he wants to pass on some crucial ninja skills or knowledge that only he can teach. Another reason might be the strong father - son bond. Despite being separated for so long, Minato's love for Naruto is still very deep.
Some members of the ANBU themselves could be antagonists. They might think that Naruto belongs with them and that Kushina is interfering in their affairs. They could try to keep Naruto in the ANBU by any means necessary, including using force or setting up traps for Kushina when she tries to approach Naruto.
Maybe a new group of rogue ninjas who see Naruto as a threat to their plans. They've kidnapped him and are holding him captive. Anko would then have to fight these ninjas who are well - trained and have their own unique abilities. They might be after Naruto's Nine - Tails chakra for some evil purpose.
His mother, Kushina, could also be part of the family that wants him back. She was a kind - hearted and strong - willed woman. If she were alive in the fanfiction, she would be desperate to have her son with her. She would want to protect Naruto and share all the things she didn't get to when he was growing up, like teaching him about their Uzumaki heritage.