The Stunning Little Princess of the Devil World

She, an ordinary student in the school, her greatest wish is to use her knowledge to find her missing sister He, the king of the demon world, controls the demon world, one of the six realms, but he is so cold and silent about everything. Two different time and space, two people who cannot possibly meet, what kind of story will happen between them? Was her time travel and her encounter with him an accident or an entanglement from her past life? The update in July will be slow, please forgive me.