Kim Soo-jin, the woman who opened my eyes to the castle! But as soon as I enlisted, I put on my rubber shoes upside down… with the huge US Army…!! Unable to forget the hot night with her, he suddenly became a troublemaker and a soldier of interest to the unit. Then one day, Sohee’s older sister, whom she had a crush on when she was young, started visiting. Become my brother’s girlfriend…!!