One plot idea could be that Loki has been captured by a powerful new enemy who wants to use his knowledge of Asgardian magic. The Avengers find out and embark on a rescue mission. Along the way, they face various traps set by the enemy. Another could be that Loki fakes his own capture to draw out a threat that he can't handle alone, and the Avengers come to his aid not knowing it's a ruse at first.
Well, a cool plot could be Darcy discovers a hidden power within herself while being around Loki. Loki, intrigued by this, decides to help her master it. Along the way, they face challenges from both Asgard and Earth. Maybe some Asgardians think Darcy is a bad influence on Loki and try to separate them. Meanwhile, on Earth, SHIELD is also suspicious of their alliance. It could lead to a lot of action and some unexpected friendships and romances.
A more complex plot could be Loki impersonating Black Widow. He infiltrates the more covert operations of the Avengers. While in her form, he could plant false intelligence, leading the Avengers into dangerous situations. He could also use her relationships with the other members, like Hawkeye, to create emotional turmoil within the team, all while trying to achieve his own goals of taking over the world or getting his hands on powerful magic items.
A plot could involve Loki using his agent skills to manipulate the Avengers into a false sense of security. He then reveals a master plan that involves using their own powers against them to take over Earth. But in the process, he starts to have second thoughts as he gets to know the Avengers better and forms unexpected friendships. For example, his interactions with Black Widow could lead to him seeing the value in human relationships.
One idea could be Loki's struggle to hide his condition from the other Avengers. He might be worried about how they'll react, especially Thor. Another plot could involve a character, perhaps a new Asgardian healer, trying to find a way to ease Loki's discomfort during this time.
One idea could be Loki's struggle to control his 'in heat' state while trying to deceive the Avengers. He might have to constantly hide his true feelings and symptoms, which could lead to some comical yet tense situations.
Well, a plot could involve Loki and Jane being accidentally transported to a parallel universe where their roles are reversed. Jane has to deal with the politics of Asgard while Loki tries to understand Earth's scientific concepts. Or, perhaps they are both caught in a time - loop where they keep repeating a day, and they have to figure out how to break it together, learning more about each other in the process.
In the 'Avengers and Loki Christmas fanfiction', it could be that an ancient Christmas - themed evil force is awakened. The Avengers are initially baffled on how to deal with it as it uses Christmas magic in a malicious way. Loki, having knowledge of both magic and trickery, offers his help. Together, they go on a journey to find the source of this evil. Along the way, Loki and the Avengers have many arguments and moments of understanding. By Christmas Eve, they manage to defeat the evil force, and Loki stays with the Avengers to celebrate a well - earned Christmas, having become a sort of honorary Avenger for the time being.
One idea could be that Loki's kids inherit his shape - shifting ability and use it to outwit the Avengers while also trying to find their place in the world. They might be initially seen as threats but then prove to be valuable allies.
A really cool plot idea could be that the Avengers are watching Endgame in a sort of 'alternate reality cinema' where the events in the movie start to bleed into their real world. So they have to stop the movie from fully playing out to prevent chaos in their own universe. This would involve a lot of action and strategic thinking as they try to stop things like Thanos from emerging from the screen while also trying to understand the significance of what they're seeing in the movie.
A plot could also revolve around a time when Rescue's identity is compromised. Iron Man has to protect her while also trying to figure out who is behind the leak. They go on a journey that takes them to different parts of the world, facing various threats along the way. This would test their relationship and their ability to trust each other in difficult situations.