Yotsunoha(2008)

Yotsunoha is an anime series based on the visual novel by Haikuo-Soft. Four childhood friends—Yuzuki, Matsuri, Nono, and Makoto—reunite at their abandoned school, Mochitsuki Academy, to fulfill a promise made three years earlier. They had buried a time capsule beneath a tree and vowed to return on this exact day. As they gather again on the deserted campus, the friends must confront how much has changed since they last met and what the passage of time has meant for their bond. The series blends nostalgia with the bittersweet reality of growing up, exploring themes of friendship, memory, and the weight of promises kept.