One Nation, Two Cities (2011)

Every three months, a Chinese single mother, Xue takes a 10-hour-journey from Hong Kong to her hometown in Fujian, China with one hand dragging her heavy luggage and another hand holding her child. She has to extend her visiting visa to stay with her family, which migrated to Hong Kong when she was 8. In 1980s, the Chinese local government would let the family migrate except one child, so they would send money back. The tragic starts from here.