1978年，在釜山发生的真实的故事 一个孩子被诱拐，刑警孔吉勇受孩子父母的特别嘱托，负责此次案件。为了保护孩子，他决定秘密搜查。一方面孩子的家人寻访各个有名的算卦店，来确认孩子的生死，得到的回答却是孩子已死，最后找到了道士金钟山。 ‘孩子肯定还活着’ 金道士用孩子的生辰八字算卦，确信孩子还活着，并且半个月后罪犯会第一次联络。如金道士所言，在孩子失踪半个月的时候接到了罪犯的电话，孔吉勇通过罪犯提供的线索确信了孩子还活着，开始相信金道士的话。但是过了一个月，搜查依然没有进展。比起孩子的生死，所有人更为寻找罪犯急红了眼，只有金孔吉勇和金道士两个人继续为拯救孩子展开搜查。

在台湾基隆港东北220公里处的海面上，一艘装载着核卫星导航装置的舰艇离奇失踪，经过调查确定他被一个名叫信（张东健饰）为首的海盗团伙夺取。在1983 年，年幼的信跟随全家人从北朝鲜逃往韩国寻求政治庇护，却被韩国政府拒之门外，除信和姐姐明珠（李美妍饰）得以逃生之外，其他人员均遭杀害。姐弟二人自此失去了联系，后来信成为海盗，对韩国的仇恨与日俱增，最终引发了现在的挟制核舰艇事件。

根据韩战期间真实战事改编。1950年6月25日，北韩挥军越过三八线突袭南韩，三日攻陷汉城（今首尔），战线不断南进。在美军及联合国军支援下，南韩军逆势反击。美军指挥官麦克亚瑟提出代号为「铁铬行动」的仁川登陆计划，该计划急需一支大队的兵力从侧翼阻击扰敌、声东击西，通过长沙里切断北韩军的补给线。 由于任务本身极其艰钜，加上南韩国军当时兵力薄弱，无法抽调足够正规军支援，军方不得不把这项任务交付给772名学生兵执行，这些学生兵平均年龄只有17岁，仅仅接受了两星期的军事训练，在毫无实战经验的情况下投身战场。行军路上固然杀机重重，战友内部也诸多衝突，年少气盛，迸发出各种角力。 仁川登陆战前夕，长沙里登陆任务如期执行，这群徒有一腔热血但战力薄弱的学生们，无可避免地接受命运中最残酷的考验：穿越炮火与海浪，浴血长滩，馀下部队身陷敌军重重围剿，直至弹尽粮绝，挣扎于阵亡与倖存的分界线上… Based on the incredible true story of Jangsari Landing Operation. When North Korea invades South Korea on June 25, 1950, they pushed South Korea and its ally US Army to the southernmost city. U.S. General MacArthur planned Operation Chromite, which would see the joint allied forces to take back a strategic location of Inchon and in order for it to succeed, he needed a small battalion to flank the North Korean army and eliminate their supply line at Jangsari beach. Having lost his family on his retreat away from North Korea before the War, a model student Choi Sung-pil enlists in the army to fight for the South. Ki Ha-ryun is a rebellious youth from the South who volunteers to fight in the war. All of the 772 students and youths are like them who are barely out of school with only 2 weeks of boot camp training. Task force mander Captain Lee Myung-jun knows that it’s a long shot, but he has no choice but to lead them into a crucial mission. Meanwhile, US war correspondent Maggie braves the dangers of the battlefield to report on the war in the frontlines. She feels empathy for the Korean students who must go into battle on behalf of the veteran soldiers for their country, and tries to do what she can on her end to rescue them. With little ammo, scant food supplies and raggedy weapons, can the students successfully carry out their mission and return home safely?

电影《朋友2》是由前作《朋友》的导 演郭暻泽继续执掌导筒，继续前作的故 事，而主角从刘五性和张东健变成了他们 的儿子们。