Kaguya-sama wa Kokurasetai: Tensaitachi no Renai Jinrosen

The time is after Kaguya and Shirogane start dating, but before the final battle with the Shinomiya family. The setting is Tsukikagekan, which stands on a solitary island owned by the Fujiwara family. In addition to the members of the student council, Fujiwara Moeha and Shirogane Kei are involved in a battle similar to a werewolf game over a treasure that can make wishes come true!