Based on an real historical event in Cambodia from 75s to 85s I guess. A coup happened in Cambodia, led by Khmers. The Khmers killed so many innocent residents in Cambodia and in Vietnam too-as who is living near Cambodia border. The Khmers wanted to attack and invade Vietnam but Vietnamese didn’t want another war because they just ended their war with the US a few years ago. Both Vietnamese and Cambodia government decided to let Vietnamese army go to Cambodia land to help Cambodia rebuild their government and political systems. That’s why you’ll see in this movie, Vietnamese water is just couple miles away from Cambodia land. For anyone who didn’t know, after Cambodia government protect themselves and their country, Vietnamese government withdrew its troops.