During the Korean War, Second Lieutenant Han Sang-yeok has lost his faith, but he still perseveres in his duties as a military officer. Sang-yeok encounters a children’s choir. They open up his heart with their optimistic attitude. Sang-yeok joins piano teacher Park Joo-mi to teach the children to sing. As Sang-yeok helps the children, he rediscovers the meaning of his being on the battlefield.