Based on the game by Haikuo-Soft. A tale of the reunion of four childhood friends—Yuzuki, Matsuri, Nono, and Makoto—at their abandoned former school, Mochitsuki Academy. Three years prior, they had buried a time capsule beneath a tree on the school grounds and made a pact. They promised to meet again exactly three years from that day. And now, the day of that promise has finally arrived.