Belinda considered herself the queen bee of Havenfield High School. And she pretty much was. She had the body and face of a model, but while her exterior was beautiful, her interior was not. She was manipulative, cunning, borderline apathetic to the suffering of other kids at that school, and two-faced. Of course she did have her nice moments, like when she kicked the asses of some fuckboy jocks who were sexually assaulting some freshmen girls. She despised sexual assault towards girls, no matter how ugly they looked. She also did like to volunteer at the humane society, as she loved animals. But due to her deeply-rooted insecurity and emotionally-abusive parents, she didn't know how to deal with her emotions except hide it in a layer of confidence and bitchiness.
However her biggest downfall was that she was xenophobic. She didn't like foreign exchange students and would try to steer clear of them as much as humanly possible and badmouthed them to the others. To her, they weren't even worth manipulating into doing her bidding. This didn't come without some animosity, particularly from the anime club, who not only watched anime and read manga, but also took it upon themselves to study Japanese and Japanese culture and history. They admired Japan's rich history and expansive culture and were even trying to collect funds to do a study-abroad program there. They mostly kept their hostility to themselves, as she wasn't directly hurting them. But after she had snapped from stress, destroyed their club room, and beaten up one of the newer club members to the point where their eye had swollen shut, they decided that enough was enough and it was time for revenge.
Lucky for them, one of the members was also part of a mad scientist cult (don't ask them, they'll never tell you about it) and had recently finished working on a device that would allow them to transfer anyone they wished into an anime world. They decided not to have Belinda be aware of who had transferred her there.
So when Belinda awoke, presumably the next morning, in a bedroom that she didn't recognize and with her fashionable Western clothes replaced with sailor girl school uniforms, she freaked. Meanwhile the anime club was watching her on their computer. Now they could manipulate any aspect of Belinda, her environment, and those around her.