Kuro to Kin no Akanai Kagi.

After a painful start at school led her to retreat into her home, Kanade cuts her overgrown hair and begins trying to face the outside world again. Reconnecting with other people means confronting the anxiety that has kept her isolated and taking tentative steps beyond the life she has shut herself inside.

Her stepbrother Ikuto watches this change with increasingly conflicted feelings. As Kanade seeks greater independence, his attachment to her strains their relationship, bringing the boundary between caring for someone and trying to keep them close into question.