One day at early dawn, a search unit near the DMZ, the front line, is on alert. 
It was because a soldier from another unit’s GP ran away to DMZ with a gun. Under Commander Baek, the 3rd platoon members led by First Lieutenant Cho are put into the operation to arrest the deserter. The search begins, and at the same time, First Lieutenant Lim's dead body is found at the unit’s official residence. The accident is reported to the Division Headquarters and Captain Kang, who is about to be discharged, arrives at the search unit with an army surgeon. The commander and the army surgeon are rushing to conclude Lim’s case with suicide, but Kang suspects that there is a deep secret in this accident. At that time, the soldiers who were put into the operations get killed one by one, and the dark truth between Lim’s death and the deserter search operation is revealed.