A possible plot could be that the Goblet of Fire starts acting strangely. McGonagall notices some odd magical fluctuations around it. She enlists the help of Hermione, knowing her academic prowess. Together they try to figure out what's wrong. Meanwhile, Harry has a strange feeling about it all. Eventually, they discover that a dark wizard from the past is trying to use the Goblet to return. And they must stop it before it's too late.
Well, there could be a fanfic where McGonagall is put in charge of security for the Goblet of Fire event. She asks Hermione to be her assistant in a way, to help with research and detection spells. Harry, being Harry, gets caught up in some mystery surrounding the Goblet. He comes to McGonagall and Hermione for help. They then start an investigation that leads them to discover a conspiracy within Hogwarts itself, with some students trying to use the Goblet for their own, not - so - noble purposes.
An interesting plot might be that Hermione stumbles upon a prophecy related to the Goblet of Fire. She tells McGonagall, who then realizes it has implications for Harry. They try to keep Harry in the dark at first to protect him, but he finds out anyway. Now, all three of them have to work together to either prevent the prophecy from coming true or to use it to their advantage against the rising dark forces that seem interested in the Goblet's power.
One great fanfic could be about Harry and Hermione getting unexpected advice from McGonagall regarding the Goblet of Fire. Maybe McGonagall suspects some foul play early on and warns them to stay away from it, but their curiosity gets the better of them.
Perhaps Harry is transported to a time in the past during the Goblet of Fire event. He could interact with the founders of Hogwarts, and they could give him advice on how to deal with the dark forces that are at play in his own time. This would add a historical and magical depth to the fanfic.
Well, it could be that Hermione accidentally drinks a love potion during the Goblet of Fire events. Harry is the only one who can break the spell. The 'lemon' aspect might be some flirty and slightly spicy interactions as Harry tries to bring Hermione back to normal. For example, a scene where Harry has to hold Hermione's hand a bit longer than necessary while reciting a counter - spell.
The fanfic might revolve around Harry's interaction with the Goblet of Fire due to a misunderstanding. He could think that the goblet is being influenced by dark magic and decides to investigate. As he messes with it, he discovers some hidden secrets about the Triwizard Tournament and its origins. This could lead to him having to make difficult choices to protect the integrity of the tournament and Hogwarts, all while dealing with the consequences of his meddling with such a powerful magical object.
One interesting plot twist could be that Hermione discovers a hidden spell within the Goblet of Fire that no one else knew about. This spell could change the nature of the Triwizard Tournament in unexpected ways.
One possible plot could be Harry discovers a hidden training ground within Hogwarts. He meets a mysterious old wizard there who teaches him unique spells and combat techniques specifically for the Triwizard Tournament tasks. This wizard could have some connection to the founders of Hogwarts, and his teachings give Harry an edge in the tournament.
Well, a plot could involve Harry and Hermione being forced to enter the tournament together as a pair, against the rules. They then have to face challenges that are not only dangerous but also designed to test their relationship. For example, in one task, they might have to choose between saving each other or winning the task. This would create a lot of drama and tension between them. Also, there could be a sub - plot where they start to realize their feelings for each other during the tournament.
Another plot could involve Hermione using her vast knowledge to help Harry train for the tasks in the tournament in a more unique way. For example, she might find a way to combine ancient magic with modern spell - casting techniques. This could lead to some really exciting and unexpected moments during the tasks.
One interesting plot twist could be a different champion being secretly controlled by Voldemort instead of just Barty Crouch Jr. as the imposter Moody. Maybe a champion from a different school who no one suspects.
One idea could be exploring what would happen if a different student was chosen by the Goblet of Fire. Maybe a Muggle - born student who has to face extra prejudice during the Triwizard Tournament. It would add a new layer of conflict and show how the wizarding world reacts to a 'less likely' champion.