A member of Coast Guard Platoon 23, Private Kang monitors a high-infiltration stretch of beach lined with barbed-wire fencing. Driven by the belief that killing a spy is the highest honor, he waits for a chance to prove his worth.

A division of marines survive a battle with the Chinese army but find themselves stranded without contact on the wrong side of the front.

Yu-mi applies to a marine outfit to become their first female member. Finding out about their NO woman-policy, she pushes herself to the extreme and fils a petition. After overcoming many obstacles, she is finally accepted for her outstanding performance. However, conflicts never cease between sergeants and Yu-mi, who’s new to the tradition and culture of the marines. Following the sudden death of a trainee, Sergeant HA, she is appointed to the head of the team. Highly motivated Yu-mi loses her troupe's trust after losing IBS. The team is in danger of dissolution due to the loss of a magazine.

A brigade of five marines are sent on a dangerous mission to capture an enemy stronghold during the Korean War.

As the Korean War draws to a close and both sides conducting truce talks in 1952, the U.S. Intelligence Agency finds out that North Korea is preparing germ warfare through aerial reconnaissance. The U.S. army decides to train and send in the invincible members of the marine corps.