beta
Translated from release post (pixiv) https://www.pixiv.net/artworks/67332467 BDP3rd... I couldn't a...
This one doesn't really make sense unless you follow BanG Dream. So I'll give a plot rundown so it'll make some form of sense.
Hina, the main girl of the story, she thinks of her sister fondly but something happened between them (the older sister's sibling complex) which caused them to fall out.
They are repairing their relationship currently within the series. And it also seems to be the case here, but Sayo, the older sister, got a girlfriend. And it brings out Hina's abandonment issues.