GP是休战线边上非武装地带最前沿警戒区的哨兵,是冷战后的余留兵。07年五月的一个雨夜,GP506的20名队员全部被一名士兵所杀,由于506的队长乃是总参谋长的儿子,军方对此事高度紧张,派出卢搜查官(千浩振 饰)负责在一夜时间内调查出事件真相。搜查队当夜进入506驻防的戒哨营,除了存活的嫌疑人士兵姜春元(李英勋 饰)外,本应20具的尸体少了一具,搜查队发现了自称是506队长柳中尉(赵显宰 饰)的幸存者,后者惊魂未定,拒绝透露任何事件经过,然而大雨阻断了道路,无法离开戒哨营的柳中尉只得描述506哨所队员感染病毒的隐情。原来该小队部分队员罹患感染后变得极富攻击性的莫名传染病,队长为了保住仕途拒绝上报,这引发了部下的哗变和最终的屠杀……(Korean with English subtitles) A squad of Korean soldiers is sent to investigate a guard post that overlooks the DMZ. Seemingly deserted at first, the squad eventually discovers mysterious corpses and body parts strewn all throughout the post. Amidst the macabre scene they discover one survivor with a bloody ax in his hand, but soon he falls into a coma, leaving more questions unanswered.