A regular Nanjing high school student, Bai Yang, accidentally connects via a mysterious radio to a post-apocalyptic world twenty years in the future, where humanity has vanished. Through this eerie link, he encounters Ban Xia, the last surviving human in Nanjing—a lone, isolated girl. As their cross-temporal bond deepens, their shared faith and determination transform their solitary struggle into a united force. Together, across time and space, they uncover the tragic truth behind humanity's extinction and lead a courageous, bittersweet rebellion to redeem the fate of humankind.