One possibility could be that Ginny is influenced by dark magic or a powerful enemy. Maybe she's forced to betray Harry to protect her family. For example, Voldemort's remaining followers could threaten to harm her family if she doesn't spy on Harry and give away his secrets. Another idea is that there could be a misunderstanding. Ginny might think she's doing the right thing for Harry, but it ends up looking like a betrayal. For instance, she could be trying to help him by making a deal with someone she believes is good, but who actually has ulterior motives.
The plot could involve Ginny being under the influence of a love potion. Someone might use it on her to make her betray Harry. She could be made to steal important magical items from Harry or lead him into a trap. It's also possible that Ginny has a secret past that she's been hiding from Harry. When it's revealed, it makes her actions seem like a betrayal. For example, if she has some connection to a dark wizard family that she never told Harry about.
Harry would probably be heartbroken. He trusts Ginny deeply, so her betrayal would be a huge shock. He might initially be in denial, not wanting to believe that Ginny could do such a thing.
One possible plot could be that Percy, who has some hidden motives or is being manipulated, leaks the Avengers' secret strategies to their enemies. Maybe he was promised power or something in return. This would lead to the Avengers facing unexpected and difficult battles as their foes seem to anticipate their every move.
One possibility could be that in a ninja world setting, Sakura and Hinata are forced to betray their friends due to a powerful enemy's blackmail. Maybe the enemy has kidnapped their families and threatened to harm them if they don't cooperate. This could lead to a rift in their relationships with Naruto and the others.
One possible plot could be that Ash is forced to give up Charizard in a high - stakes Pokémon battle. Maybe a powerful trainer challenges Ash and demands Charizard as the prize if he loses. Ash, being a proud trainer, doesn't expect to lose but due to some unforeseen circumstances, like a new and unknown Pokémon move used by the opponent, he loses the battle. Charizard, being sent to the new trainer, initially resists but is somehow forced to obey. This makes it seem like Charizard has betrayed Ash as it has no choice but to follow the new trainer's commands.
One possible plot could be that Ash and Brock are lured into a false sense of security by a powerful new trainer. This trainer seems friendly at first but then secretly uses their Pokémon to undermine Ash and Brock during important battles. Ash and Brock might start to suspect something when their Pokémon keep getting mysteriously weakened. Eventually, they realize they've been betrayed when the trainer reveals their true intentions of trying to take over their region's Pokémon league.
One possible plot could be that Cynthia, perhaps in a quest for power or influenced by some dark force, betrays Ash. Maybe she steals his Pokémon to use in her own battles or to offer to a powerful villain in exchange for something she desires, like rare Pokémon or access to a powerful training ground.
In this fanfiction's afterlife, Harry and Ginny might be in a place where time has no meaning. They could be constantly surrounded by a warm, golden light that represents all the love and positive energy they've created during their lives. They start to discover hidden powers within themselves that allow them to shape the afterlife realm. For example, they might create beautiful gardens filled with magical plants that only exist in their memories from Hogwarts. Their relationship becomes even deeper as they work together to make this afterlife place a haven for other souls.
Maybe in this fanfiction, they are at the lake to practice some magic. Ginny could be showing Harry a special spell she learned, and they end up having a little magical adventure right there by the lake. For example, they might accidentally summon some friendly magical creatures from the water.
Well, it could be about a friendly duel for practice. Maybe they are trying out new spells they've learned at Hogwarts. Harry might use his signature spells like Expelliarmus, while Ginny shows off some of the more advanced spells she's picked up from the D.A.
Well, one idea for the 'Harry and Ginny elope fanfiction' plot is that Ginny convinces Harry to elope. She's always been a bit of a rebel. They might leave Hogwarts in the middle of the night using magic to cover their tracks. They could end up in a magical forest where they discover new magical creatures and have adventures together, all while keeping their elopement a secret from their families.