Seo Joon-yeol

In 1951 ceasefire is declared, but two remaining armies fought their final battle on the front line Towards the end of the Korean War, a South Korean battalion is fiercely battling over a hill on the front line border against the North in order to capture a strategic point that would determine the new border between two nations. The ownership of this small patch of land would swap multiple times each day. Kang is dispatched to the front line in order to investigate the tacit case that’s been happening there.

Joon-soo learns that his friend Hee-gyu's sister Hee-jin has no where to go after being scammed, so he suggests living with him. The two start living together. They are close like brother and sister but they can never be that. The two start getting funny and Joon-soo can't go to sleep at the thought of Hee-jin sleeping just a wall away from him. Mi-na, Joon-soo's girlfriend notices Joon-soo changing and seduces Joon-soo at his house where Hee-jin is. Is it the girlfriend or the sister?