When Lin Chen was 5 years old, he met Lu Lu, a little troublemaker who could never get rid of him in his back garden. However, the little troublemaker had no consciousness of being dependent on others. He stayed behind Lin Chen with a smile all day long. Only when Lin Chen threatened to abandon him, his eyes that seemed to be filled with starlight would blink, and then tears would fall instantly, and the culprit would always be busy. He hurriedly took out a handkerchief and covered Lu Lu's face. He quickly ran to his bedroom and took out the airplane model imported from the United States. Then he watched with pain as it was being ravaged by Lu Lu. After Lu Lu stopped making trouble, he carefully took the model and put it back in the bedroom. Every time Lu Lu was comforted, he always softly called Lin Chen "brother", and this "brother" stayed with Lin Chen all his life!