'Brave 18' is about two girls, Kim Eun-Jeong and Choi Mi-Gyeong. Kim Eun-Jeong was taken advantage of her kindness and while she was in love, her boyfriend Lee Ji-U wasn't satisfied enough so he intended to hurt Eun-Jeong by dating other girls in front of her. In the other hand, Choi Mi-Gyeong is a beautiful popular girl, however Mi-Gyeong have a big secret no one know, she was deaf. What happen to these two girls meet when their school was bombed and unknowingly got involved in a war. Jung Byeong-Ho, a soldier who lost his way during the war found his way to the school after hearing the bomb, how will Kim Eun-Jeong, Choi Mi-Gyeong, Lee Ji-U, Jung Byeong-Ho survive in this bloody war?