It could also be a miscommunication situation. Alice might have misunderstood Bella's actions as a threat to their friendship or group. So in her haste to stop what she thinks is a bad situation from getting worse, she takes these extreme measures. However, once the truth comes out, there will be a lot of apologies and mending of the relationship.
Well, it could be a story about a prank gone wrong. Maybe Alice is playing a really extreme prank on Bella for some reason. For example, they could be in a competition within their group and this is Alice's way of getting an upper hand in a really silly way.
Perhaps it's a part of a mystery plot. Bella might have witnessed something she shouldn't have, and Alice, who is trying to protect someone or something, has to keep Bella quiet for a while until she can figure out what to do. So she ties her up and gags her in a rather drastic but necessary (in her mind) way.
Alice and Bella are likely characters from a particular fandom. They could be characters from a book series, movie franchise, or some other form of media that has a group of fans (gp stands for general public or group of fans). Without more context, it's hard to say exactly which fandom they belong to.
It could be a story about a power struggle. Maybe Tanya has some sort of vendetta against Bella and tying her up and gagging her is her way of getting revenge or gaining an upper hand in a conflict within the world of this fanfiction's setting.
They could be two characters from an existing fictional universe that the fanfiction is based on. Maybe they are rivals within a group, or they have different loyalties that put them at odds with each other.
One possible plotline could be a rescue scenario. Maybe her friends discover she's in this state and they have to outwit the captors. For example, Harry could use his invisibility cloak to get close and free her.
It could be a new dark wizard or witch who is trying to gain power. They see Hermione as a threat due to her intelligence and magical abilities, so they immobilize her to stop her from interfering with their plans.
I'm not sure specifically as I haven't read that exact fanfiction. It could potentially be about a conflict or a strange situation between Victoria and Bella. Maybe Victoria has some ulterior motives for tying Bella to the bed, like trying to keep her from interfering in something.
One reason could be that the reader has stumbled upon a secret. For example, if the story is set in a world of spies, the reader might have accidentally overheard some top - secret information and the villains want to keep him quiet.
One possible plot could be a mystery thriller. The girl is tied and gagged during a webcam session, and it's part of a ransom situation where the kidnappers are using the webcam to send messages to her family for money. Another could be in a horror context, where she is a victim of a deranged person who likes to terrify his victims on webcam.
Another common theme is adventure. Many fanfictions have them going on various adventures together, whether it's exploring new parts of the vampire or werewolf world or solving mysteries. It adds an exciting element to their relationship.
One key element is the relationship between Alice and Bella. It's often at the heart of the story, whether it's a friendship or something more complex.