根據(jù)韓戰(zhàn)期間真實戰(zhàn)事改編。1950年6月25日，北韓揮軍越過三八線突襲南韓，三日攻陷漢城（今首爾），戰(zhàn)線不斷南進。在美軍及聯(lián)合國軍支援下，南韓軍逆勢反擊。美軍指揮官麥克亞瑟提出代號為「鐵鉻行動」的仁川登陸計劃，該計劃急需一支大隊的兵力從側(cè)翼阻擊擾敵、聲東擊西，通過長沙里切斷北韓軍的補給線。
　　由于任務(wù)本身極其艱鉅，加上南韓國軍當時兵力薄弱，無法抽調(diào)足夠正規(guī)軍支援，軍方不得不把這項任務(wù)交付給772名學(xué)生兵執(zhí)行，這些學(xué)生兵平均年齡只有17歲，僅僅接受了兩星期的軍事訓(xùn)練，在毫無實戰(zhàn)經(jīng)驗的情況下投身戰(zhàn)場。行軍路上固然殺機重重，戰(zhàn)友內(nèi)部也諸多衝突，年少氣盛，迸發(fā)出各種角力。
　　仁川登陸戰(zhàn)前夕，長沙里登陸任務(wù)如期執(zhí)行，這群徒有一腔熱血但戰(zhàn)力薄弱的學(xué)生們，無可避免地接受命運中最殘酷的考驗：穿越炮火與海浪，浴血長灘，馀下部隊身陷敵軍重重圍剿，直至彈盡糧絕，掙扎于陣亡與倖存的分界線上…
　　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 commander 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?