Into the Fire Oh Jang-beom who is an South Korean student, is fighting in the Yeongdeok, North Gyeongsang Province battle during World War II. In the midst of the battle, the city is taken over by the 766th Unit, 5th Division, Korean People’s Army He is dragged into a squad consisting of South Korean soldiers led by Lieutenant Kim Jun-Seop who is trying to escape. But the group is eventually cut down to just Lt. Kim and Jang-Beom. A North Korean suddenly shoots and bayonets the lieutenant. Jang-beom due to his inexperience and terror cannot save himself. The two are found by other South Koreans, and barely make it onto one of the last truck that leave the town for an emergency hospital in Pohang, in which Lt. Kim dies with a guilty Jang-beom by his side. Into the Fire HD
Capt. Kang commands Jang Beom, one three volunteers with combat experience to lead the newly-recreated student soldier unit. Three young criminals under the leadership of Ku Kapjo, join the unit and destroy the students’ food supply. While on patrol they are snatched by a KPA Sniper who takes them into an ambush. Prior to disengaging, they sustain heavy casualties. The students’ morale is shattered by the disastrous incident. The students call Capt. Kang for help however, the forces of regular soldiers are pinned to the Nakdong River. Kang pleads with his superiors for help to pupils, however they do not want to divert resources from the crucial Pusan front. Kang is permitted to leave, but they allow him to travel in vehicles and a small contingent of South Korean soldiers to help the school.
Major Park Mu-Rang interrogates Dal-Young, one of the students captured by the 766th Unit. Mu-Rang feels sorry for the student and orders his return to the school, going there himself to evaluate the students’ capabilities. Jang-Beom receives a warning from Mu-Rang that the group will capture the school in just 2 hours. He offers to spare the lives of the attackers in the event that they raise a white flag. Kap-Jo slays Dal-young and then fights Jang Beom. He leaves along with a companion, Chang-wu to escape the Pusan Perimeter. After leaving, they encounter an North Korean truck with weapons and supplies, which is trapped on a road.
The remaining students prepare to defend their school, waving not a white flag but the South Korean national flag, while Major Park prepares himself for the attack. The attack starts, the students are able to inflict devastating casualties on the North Koreans, but are eventually forced back. The North Korean supply truck, driven by Chang-wu, Kapjo and others, abruptly is roaring into. They cut through North Koreans and bring valuable heavy weapons to the students.
The 766th’s troops enter the school building under the cover of tanks , and take out the majority of students. Jang-Beom, Kap-Jo and the other North Koreans fight their way up to the roof where they’ve put up machine guns. The roof is where Jang-beom and Kap-jo try to hold back the North Koreans.
Just as Jangbeom and Kapjo have run out of ammunition Capt. Kang and the South Koreans arrive. They take out the North Korean tank and steadily defeat the North Korean infantry in the school campus. Major Park arrives at the roof and kills Kapjo. Jang-beom has already exhausted from his wounds and exhaustion. Park is giddy while Jang-beom quietly loads his rifle, and shoots Park as Park himself. Later, Capt. Kang. Kang is comforting Jang-Beom as she suffers from injuries.
It turns out that 48 of the 71 students died in the course of protecting the school. The movie ends by flashing back to an Army photographer making a group shot of the soldiers in the school before the regular troops leave to go to Pusan, and the surviving veteran students, who are now aged look back on their experience.