Why are you always smiling?

Three schoolgirls in uniforms stand in a classroom, one holding a red object while the others react with laughter and gestures; the scene cuts to a close-up of a boy with a serious expression, then to a girl's eye with a tear, followed by a hand reaching out, a boy speaking to a girl, and finally a girl with a bandaged face looking distressed, all set against the backdrop of a school hallway and classroom with warm lighting.