Perhaps a plot twist is that the Beauty is actually a parahuman with a power that she doesn't fully understand until she meets the Beast. Their connection then unlocks a new aspect of her power, changing the dynamic between them and their goals. For example, her power could be related to empathy, and the Beast's presence intensifies it to the point where she can influence the emotions of other parahumans around her.
One interesting plot twist could be that the Beast is actually under a double curse. Not only is he a beast, but he also has a memory curse that makes him forget his true self. When Belle discovers this, she has to find a way to break both curses.
One idea could be exploring the Beast's past more in - depth. Maybe show his life before the curse and how it affected his personality. Another could be a modern - day retelling where Belle is a scientist trying to find a cure for the Beast's curse.
One interesting plot twist could be that Belle actually has a hidden power that she discovers while in the Beast's castle. This power could be related to time-travel, which ties into the 'Back in Time' aspect. Maybe she can manipulate time to prevent certain events from happening in the past, like the Beast being cursed in the first place.
It might re - interpret it by setting the story in the Worm universe. Instead of a traditional castle, the Beast could live in an abandoned parahuman - made structure. The Beauty may not be a simple village girl but a parahuman herself.
A great plot twist could be that the 'beast' is actually a dark wizard in disguise. He pretends to be cursed to lure in the 'beauty' who is a powerful young witch. But as the story progresses, she discovers his true identity and has to use her magic to defeat him instead of breaking a curse with love.
One idea could be that Belle discovers she's pregnant shortly after the curse on the castle is fully broken. This could bring a new sense of joy and anticipation to the castle. The Beast, now a prince again, might be both excited and a bit nervous about becoming a father. He could start making preparations like renovating a special nursery in the castle. Another idea is that during Belle's pregnancy, some of the enchanted objects in the castle could take on new roles as babysitters or helpers, adding a touch of magic to the pregnancy journey.
One idea could be that the sister of Beauty is a healer. She secretly tries to find a cure for the Beast's curse while also getting to know him in a different way than Beauty does. This could add a new layer of relationship and mystery to the story.
In a genderbend fanfic, the female Beast could be a sorceress who was betrayed and cursed. The male Beauty could be a traveling minstrel. His music has the power to soothe her and as he stays in her enchanted castle, they start to understand each other. The Beast begins to let down her guard and the Beauty discovers her true self beneath the curse.
One interesting plot twist could be that the Beast is actually a cursed prince from a rival kingdom, and the curse was placed by an evil sorcerer who wanted to start a war between their kingdoms. Another could be that Beauty has a hidden power that she discovers while in the castle, and this power is the key to breaking the curse in a completely unexpected way. Maybe she can communicate with the enchanted objects in a way that no one else can, and they reveal a secret about the curse.
Another plot twist might be that the Beast is not actually a 'beast' in the traditional sense. In the fanfiction, he could be a wizard under a false appearance curse, and Hermione discovers this. It changes the whole dynamic of their relationship because now they are both magic - users, and she has to figure out how to break the false - appearance curse rather than the typical Beauty and the Beast curse.