In this fanfiction's plot, there could be a rift in the space - time continuum that brings Naruto to the DC Universe where the Justice League exists. The League is in chaos as their powers are being nullified by a strange force. Naruto, being a stranger to this world, starts exploring and discovers the source of the problem. He uses his own chakra to create a shield around the League members to protect them from further harm. Then, he embarks on a journey to find a way to restore their powers. Along the way, he bonds with the League members, and they learn from each other. Finally, Naruto figures out a way to reverse the nullifying force and the Justice League regains their powers and they all defeat the ultimate evil behind it.
The plot could start with Ace being in trouble in the Justice League's world. Maybe he's been captured by an enemy of the League. Naruto somehow gets wind of this and decides to help. He travels to the Justice League's realm and starts his search for Ace. Along the way, he meets some of the Justice League members who are initially skeptical of him but then see his potential. Together, they find Ace and Naruto uses his jutsu to defeat the bad guys and free Ace.
In a Naruto in Justice League fanfiction scenario, Naruto would have a lot to offer. He has a vast amount of chakra which could be used for various purposes like powering up the League's technology or creating barriers. His relationship with his teammates in Naruto like Sasuke and Sakura could be paralleled with the relationships in the Justice League. Naruto might have some initial cultural clashes with the League members as he comes from a different world, but over time, he would learn to adapt and they would learn from his unique skills and way of thinking. His Sage Mode would give him an edge in battles, allowing him to sense danger more acutely and react faster.
Well, it could be that Naruto uses his shadow clone jutsu to overwhelm the Justice League members. Maybe he'd start with Batman, using his speed and clones to catch him off guard. Then for Superman, he might use some of his more powerful jutsu like the Rasengan, powered up with Sage Mode. But it's really a wild and crazy concept as the two universes are so different in power scales and nature.
In this fanfiction, Robin could be saving the Justice League from a threat that they didn't see coming. For example, a mind - controlling parasite that has infected some of the members. Robin, being the smart and resourceful character he is, figures out a way to neutralize the parasite. He might have to go through a series of challenges, like sneaking into a heavily guarded enemy base, decrypting complex codes to find the antidote, and then distributing it to the affected League members.
A plot could be that an ancient evil has awakened in both the Naruto world and the Justice League's world. This evil has the power to drain all life, similar to how Orochimaru drains chakra. The Mokuton, being a life - giving power, is seen as the key to stop it. The Justice League travels to the Naruto world to seek help from those with Mokuton abilities. Together, they train and develop new strategies to fight this common enemy.
The plot could involve Batman saving the Justice League from a situation where they are physically trapped. Maybe they are in some sort of energy - based prison. Batman, with his detective skills, would first figure out how the prison works. Then, he'd use his gadgets like his grappling hook and batarangs to break through the prison's defenses and free his comrades.
Well, in this fanfic, perhaps the Justice League has been poisoned or mind - controlled. Batman, being the resourceful hero he is, might first analyze the situation carefully. He could then track down the source of the problem, whether it's a new super - villain or an old enemy with a new trick. He'd likely use his Bat - computer to find a cure or counter - measure and then fight his way through any minions to administer it to the League members, saving them from certain doom.
Well, in a fanfiction, anything can be possible. Naruto's skills like his shadow clones and Rasengan could potentially be used to rescue Ace. Maybe he uses his speed to get through the Justice League's defenses, which are set up around Ace for some reason. And then he uses his clones to create a distraction while he frees Ace with his combat abilities.
One plot idea could be that Batman discovers a hidden threat to the Justice League that even their superpowers can't detect easily. Maybe it's a new type of mind - controlling technology. He uses his detective skills to find the source and then devises a plan to free his teammates from its influence.
One interesting plot point could be Nightwing using his unique acrobatic skills to outmaneuver a powerful enemy that has the Justice League trapped. For example, he might swing through a complex maze - like structure created by the villain to reach and free his teammates.