beta
... The step-mum is so ridiculous...
I mean, if you hate this child so much that you would deprive her of basic education, trap her at home and isolate her from her step brothers... The least you could do is deal with her narrow world view and her obsession with you..
This woman would have sent this girl to a boarding school in Switzerland, and nobody would know who she is, prevent her from ever coming back and give her the means to stay abroad, BUT no ...
please deal with her as she systematically unravel your household