Reign of Fire (2002)

12-year-old Quinn Abercromby accompanies his mother to work one day at a London tunneling project, his witnesses the accidental uncovering of a centuries old fire-breathing dragon beast and waking it from its sleep. After witnessing the beast kill his mother the film jumps twenty years later to a grown up Quinn who is the "fire chief" in a refugee camp. Unexpectedly an American militia leader shows up at the camp with a group of men that he calls "slayers." Van Zan and Quinn engage in a power struggle, before realizing it's the dragons they should be fighting instead.