COME ONE BAES!!!HELP ME FIND THIS!!

straight story about a girl who was confined(?) in her house by her older cousin.She never went out of her house coz she is sickly and blind and her cousin(nii-chan) is apparently a novel writer so didnt went out much either.Then the editor of his brother went to their home to collect manuscript and tell the girl about the outside world.He told the girl stor bout a princess being trapped in a castle or smthing(?or not??) like she was being trapped too. And then the girl went out of her house like a step or so and then her bro saw it and then her bro scold her.And she told the bro(coz she call him nii chan) that she doesnt want to confine the bro around her anymore and that she is not actually blind but just want the bro to be with her always so she pretend to be blind.And it was pretty interesting since the bro thought he was the one who got the girl in his palm but it is actually the opposite.She then tell the editor that she doesnt like the story and it is better to be confined than being free as long as it is with someone she love or smthing....(i think they r quite a traditional family coz they wear like kimono and live in a traditional japanese home)