夜まで待てない。

Haruka and her stepbrother Tsukasa are already in love, but neither of them is good at being honest. Their closeness is filled with teasing, jealousy, and the awkward tension of living like family while wanting more. A transfer student named Jessie appears and begins openly chasing Tsukasa. Haruka is shaken further when she hears that the two once promised to marry. Their relationship is pushed forward by rivalry, secrecy, and feelings they can no longer brush aside.