Mikakunin de Shinkoukei, known in English as Engaged to the Unidentified, is a romantic comedy anime series that follows Kobeni Yonomori, a high school girl who discovers she is engaged to Hakuya Mitsumine, a mysterious boy who suddenly appears along with his little sister Mashiro. As Kobeni adjusts to her new life with her fiancé and future sister-in-law, she learns more about their strange origins and their connection to her family. The series combines humor, romance, and a touch of the supernatural.