Maybe in the fanfic, Ben Tennyson is handcuffed as part of an experiment gone wrong. He has to figure out how to use his alien powers in a limited way with his hands cuffed. His struggle could be about not only getting free but also saving the day from the chaos the experiment created.
Another possibility is a rogue member of the Plumbers (the organization Ben sometimes works with). This character might feel that Ben is too powerful and a threat, so he handcuffs Ben to try and contain him. This would lead to a conflict within the Plumbers' ranks as Ben's friends try to free him and figure out why this has happened.
One common theme is friendship. The OC and Ben often form a strong bond of friendship through their adventures. Another is self - discovery. Both the OC and Ben might learn new things about themselves when they are together. And power - combination is also common, like how their different powers work together.
Power and responsibility is also a big theme. Ben has to handle the powers of his alien forms responsibly, especially when dealing with aliens. In many fanfics, there's also the theme of discovery. Ben discovers new things about the aliens, their cultures, and their abilities. For example, he might learn a new power from an alien that he can use in a different way. There's also the theme of cooperation, where Ben and the aliens work together to achieve a common goal, like saving a planet or stopping a powerful enemy.
Well, it could be a story where Gwen Tennyson's powers from her universe somehow cross paths with the power of the Green Lantern ring. And Naruto's ninja skills and his never - give - up attitude could add an interesting dynamic. Maybe they team up to fight a common enemy that threatens all of their worlds. For example, an evil force that wants to steal the Green Lantern's power, Gwen's alien tech, and Naruto's chakra.
One reason could be that in the fanfiction, Ben is getting a lot of attention from other characters. Maybe the story has Ben in a romantic relationship with someone else, and Gwen, who has a close bond with Ben in the original series, feels left out. It could also be that the fanfiction portrays Ben in a heroic light without much focus on Gwen's role, making her jealous of the spotlight he's getting.
It could be about their adventures together. Maybe they go on a journey through a magical forest, facing various challenges like talking animals and enchanted obstacles.
The plot might involve Ben being captured by a new and powerful alien race. They could be interested in the Omnitrix technology. Ben would have to figure out their weaknesses while being held captive, and perhaps make some unexpected allies among the other captives. He'd then use his wits and the powers of the Omnitrix to break free and save the day.
The plot could be about Ben using the Benfire form to save the world from a new, fire - based threat. Maybe there's a villain who can control all kinds of fire and is causing chaos, and only Ben in his Benfire form has the power to stop it.
One possible plot could be that Esther gets caught up in an alien conspiracy in the Omniverse. Ben, being the hero, steps in to save her. As they work together to uncover the truth behind the conspiracy, they start to fall for each other.
Well, in a 'Ben 10 Omniverse Ben x Kai' fanfic, perhaps it could start with Kai joining Ben on one of his inter - dimensional adventures. Along the way, they encounter various challenges that test their relationship. Ben might use his Omnitrix in creative ways to protect Kai, and in the process, they realize their mutual attraction. For example, when they are trapped in a strange alien world, Ben has to transform into different aliens to find a way out while also keeping Kai safe from the local dangers.