Kaeri no Kai wo Hajimemasu. Ijime Saiban Kaitei

Kitami, the class representative, is struggling to help Toujou—a girl who transferred into the class in the middle of the semester—fit in better with the class. But try as he might, his effort just goes nowhere. That's the situation when one day, a theft incident occurs in class. Toujou is suspected of being the culprit and becomes the target of bullying. Kitami desperately tries to stand up for her, but he gradually becomes isolated...

(Source: Square Enix, translated)