R-Point (2004) on Netflix

On 07 January 1972, the South Korean base in Nah-Trang, Vietnam, receives a radio transmission from a missing platoon presumed dead. The high-command assigns the veteran and decorated Lieutenant Choi Tae-in to lead a squad with eight other soldiers and rescue the missing soldiers from the R-Point. When they arrive in the location, they have a shooting and defeat a Vietnamese woman with a machine gun in a trench. Later, they find a tombstone telling that one hundred years ago, Chinese killed Vietnamese, dropped them in a lake and built a temple over the place, being a sacred location to the Vietnamese. While chasing the missing soldiers, weird things happen with the rescue team.