The Front Line (2011)

Towards the end of the Korean War an uneasy ceasefire is ordered, but out on the Eastern front line of the Aerok Hills fierce fighting continues. A race to capture a strategic point to determine a new border between the two Koreas is the ultimate prize.
A bullet is then found in the body of dead company commander of the South Korean army. The bullet that killed the company commander belongs to the South Korean army. Lieutenant of the Defense Security Command Kang Eun-Pyo (Shin Ha-Kyun) is ordered to go out into the Eastern front line and investigate the murder. When Kang Eun-Pyo arrives in the Aerok Hills he is surprised to find his old friend Kim Soo-Hyuk (Ko Soo) commanding troops in the Aerok Hills. Kang Eun-Pyo believed Kim Soo-Hyuk was dead.