Nono Nekomiya, Makoto Yuki, Iori Yuzuki, and Matsuri Amachi were once the best of friends in their school's light music club. Unfortunately, their time together was cut short when their school closed down, sending them to different schools. Before they went their separate ways, the group buried a time capsule under a tree with the promise to meet again in the future. However, Matsuri left in a fit of rage, causing a rift between the friends.
Three years later, the group was reunited and discovered their old teacher had found and repurposed the time capsule as a lost and found game. As they followed the clues their teacher had left behind, the friends reminisced about their school days and found themselves overwhelmed by emotions long buried.
