Bubble Girl

Kiyomiya Ruka, a second-year high school student, has a friend named Fukaisui Suzu who has been with her since elementary school. One afternoon after school, Ruka, who has been keeping Suzu waiting, hurries to meet her, and hears groaning sounds coming from an empty classroom along the way. Curious, Ruka peeks into the classroom and witnesses a boy from the same class committing violence against Suzu.