Saint Ruri Girl\'s Academy. At this academy, there are two opposing factions: the \"Ruri Class,\" consisting of refined, well-bred ladies, and the \"Ai Class,\" made up of delinquents with poor behavior. Nanase Mitsuki, among the students of the Ai Class, is the most feared by the Ruri Class due to her intimidating appearance, though Mitsuki harbors a complex about her looks. One night, she meets Hosho Yuka, a young lady wandering alone at night... A sweet and fleeting love story between two people who are only allowed to meet at night.