The answer

A black-haired anime girl in a school uniform holds a device and brings a finger to her lips in a shushing gesture, then the scene cuts to a green-haired girl in a yellow top holding a photograph in a library, followed by the same girl standing on a rooftop, then a blurry shot of two girls in a close embrace, then a girl with long dark hair lying on a bed, and finally a bright, abstract flash of light and color.