Boku wa Imouto ni Koi wo Suru  

I'm My Little Sister's Secret, I'm in Love With My Little Sister

Yori and his identical sibling iku were once very close as kids but now yori has become distant from iku and avoids spending time with her. iku is puzzled by yori's behavior. in reality, yori harbors feelings for iku that are forbidden because they share the same room in bunk beds. to cope with his intense attraction to iku, yori tried dating iku's best friend and even applied to attend a school far away from her. however, when iku mentioned having a boyfriend and going on dates, yori's desire intensified, leading him to confess his feelings. although iku loves her brother deeply and wants them to remain together, she is not willing to be with him romantically as he desires.