Twenty-year-old Aangan dropped out of school due to illness. With unspoken confusion, he came to Wangxi School in the southwest mountainous area to teach. Here, he met Tian Yuan, a silent and steady returning teacher. One has a habit of covering up his uneasiness with dignity, and the other always hides his personal needs behind his responsibilities. The two gradually got closer while preparing lessons, visiting homes, traveling on rainy nights, and eating ordinary meals. They also had to face the distance between the city and the mountain village, their future and their family, their hobbies and their shared life. "Hello, Sir" is about a love between same-sex people that changes each other but may not lead to staying together. It also writes about leaving, staying, and how two ordinary people learn to take responsibility for their own choices.
