Female graduate student Si Lili discovers that an old mobile phone, discarded and dead for three years, suddenly rings, with the incoming call display showing the year 1919. After connecting, the other person claims to be Ye Hua, a student at Peking University. She searches through all historical records, yet cannot find any trace of this person. He asks whether China a hundred years later is well? How should she answer? A phone call spanning a century brings to light sacrifices and watchfulness forgotten by history. A prosperous age is as you wished, and you should not be forgotten.