Complex sentence: The gang leader and girlfriend are involved in the conflict between gangs of children of formerly-mainland families and those of Taiwanese, and the film places this murder incident in the context of the political environment in Taiwan at that time.
Split into simpler sentences: The gang leader and girlfriend are involved in the conflict between gangs of children of formerly-mainland families and those of Taiwanese families. The film places the murder incident in the context of the political environment in Taiwan at that time.