One idea could be that the Agents of Shield discover a new group of Inhumans with a unique power that could be a threat or an asset. They have to decide whether to help them control their powers or contain them. Another could be an Inhuman from the Inhumans group joins the Agents of Shield to help fight a common enemy, like a new alien threat. And a third idea is that some technology from Agents of Shield accidentally causes a power surge among the Inhumans, leading to chaos that both groups must work together to resolve.
Well, a cool plot might involve an Inhuman with the power to manipulate time. This Inhuman's power goes out of control and starts messing with the timeline in ways that the Agents of Shield have to fix. Maybe it causes some of their past enemies to reappear or changes events that were crucial to the formation of Shield. Also, perhaps there could be a love story between an Agent of Shield and an Inhuman, which causes some tension between the two groups as they have different views on relationships and loyalty. Another plot could be that a powerful Inhuman artifact is stolen and both the Agents of Shield and the Inhumans think the other group is responsible, leading to a big misunderstanding that they later have to work through.
One idea could be that the Agents of Shield discover a hidden threat that is related to an old Avengers enemy. For example, a Hydra remnant has found a way to re - activate some of the technology left behind by Ultron. The Agents of Shield then have to team up with the Avengers to stop this new threat. They could combine their skills, like the Agents' espionage and the Avengers' super - powers.
One idea could be that some of the Agents of SHIELD team get transported to Starling City where they cross paths with Arrow's team. They could team up to fight a common enemy like a meta - human terrorist group that has access to both high - tech weapons and ancient magic.
One idea could be that the Agents of Shield discover a new threat that is related to an old enemy of the Avengers. They have to team up to figure out how to stop it. For example, a hidden Hydra cell has found a way to re - activate an old weapon that was once used against the Avengers.
Perhaps a virus is released that targets enhanced individuals. The Avengers are directly affected, but the Agents of Shield has some research on a similar virus from a previous mission. They team up to find a cure. Along the way, they face off against a group of mercenaries who are trying to use the chaos to steal valuable technology from both the Avengers and Agents of Shield.
A fun plot could be that some of the Agents of Shield are actually Squibs or have some latent magical ability that they didn't know about. When they cross paths with the wizarding world through Harry Potter and his friends, they start to discover their magical side. This could lead to a story where they are trained in magic while also using their Shield training to help the wizarding world fight against a new threat, like a group of dark wizards who are trying to create a portal to bring in more powerful dark forces from another dimension.
Perhaps there could be a time - travel related plot. A device is accidentally activated in a S.H.I.E.L.D. lab that sends some Agents and Avengers back in time. They end up in a crucial moment in history, like during World War II. There, they meet younger versions of some of the Avengers. They have to work together without changing the timeline too much while also finding a way back to their own time.
Daisy Johnson from Agents of Shield would be really interesting. Her own Inhuman powers make her a natural bridge between the two groups. She could help the Inhumans understand the ways of Shield and vice versa. Also, Black Bolt from the Inhumans is fascinating. His power is so extreme that just speaking could cause destruction. How would he interact with the Agents of Shield? What kind of strategies would they have to come up with to communicate with him? It would be really engaging to explore.
One idea could be a story where the Agents of Shield team has to team up with some of the less - known Avengers to stop a new, powerful threat that is specifically targeting the more minor superheroes. This would give a chance to explore the dynamics between the two groups and shine a spotlight on the underrated characters.
One idea could be a crossover mission where the Agents of Shield team has to work with the Avengers to stop a powerful alien threat that is targeting both Earth and a hidden Inhuman settlement. The Agents could bring their espionage skills while the Avengers use their raw power.
An Inhumans crossover fanfiction could involve a crossover with Doctor Strange. The magic of Doctor Strange's world and the Inhumans' abilities might clash or combine in unexpected ways. Maybe the Inhumans need Doctor Strange's help to deal with a magical threat that is affecting their city of Attilan. Or perhaps they can offer something in return, like a rare Inhuman artifact that has magical properties.