When the seven siblings of the Xus are celebrating their father's birthday, the elderly man has a cerebral hemorrhage and is taken to a hospital. From the panic and confusion upon learning of their father's hospitalization, to the flustered state of accompanying them in the ward, from the helplessness of choosing to abandon treatment, to the profound regret of facing their father's death, a myriad of complex and subtle emotions intertwine. The shared grief and differing hardships among siblings, along with the struggles and downfalls of their younger generation in the era of significant transformation, crystallize into reflections and inquiries on life and death, morality, and human nature. Who Is Knocking at the Door was No. 1 in the Sixth Golden List of Chinese Novels 2021. Its audiobook is available on Himalaya, a leading online audio sharing platform in China, and it has many fans.