Back in the hot summer of 1997, Ke Da had fallen for Xia Ye during their senior year at high school, and the two had expressed their feelings to each other via audio cassettes.

Arriving in Qingdao, Xia Ye visits the Post Office of the Future, which is now run by Sun Jiaolian.

There, Sun tells her about how the Xia Ye who once loved Ke Da, was hospitalized and eventually died of leukemia.

Gradually, the mystery of why Xia Ye and Ke Da received the old audio cassettes is solved.

[4][5] The film was shot on location in Qingdao, a seaside city in Shandong province.