An international student of Beijing University of Technology (Jinaid, from Afghanistan）tasted a juice made of hawthorn，which is a very common wild fruit often eaten in his hometown. His teacher Ms. Liu told him that the raw materials of the fruit juice also exist in the rural area of Beijing, and this juice has something to do with their university. He and his foreign friend (Mafi Koloa, from Tonga) set off with Ms. Liu to explore the story behind.