Voice actress Na Xia suffers from aphonia due to work stress and moves into an old neighborhood to recuperate. Her neighbor Lu Shen is a radio host, and his nightly live broadcasts become Na Xia's only solace. The two form a bond through a thin wall and countless midnight voices. Lu Shen helps her find her voice back, and Na Xia helps him find his original aspiration. In the reinforced concrete city, they heal each other with the gentlest voices.