Xiaowen, a working-class woman, meets Bullet, a wolfdog belonging to a retired soldier, at the gate of a courtyard she passes every day. After the old man dies, Bullet refuses to eat or drink. Despite her financial struggles, Xiaowen insists on bringing him back to her rented apartment. Intelligent and perceptive, Bullet discovers an electrical leak and saves the entire building, then accompanies her to and from work day after day. While protecting his owner, Bullet is gravely injured in a struggle with a thief. In his final moments, memories of the old soldier's commands and Xiaowen's smiling face flash before his eyes, and he peacefully closes them. Later, Xiaowen becomes a veterinary healthcare worker, dedicating herself to saving more lives like Bullet's.