‘Killing Stalking’ follows Yoon Bum, a young man who suffers from several mental illnesses because of his troubled past. When Bum joins the military, a fellow officer tries to assault him sexually, and that’s when Oh Sangwoo rescues him. Without even knowing who he is, Bum becomes obsessed with the man who once saved his life. He relentlessly stalks him and also feels jealous when he finds him walking down the street with a woman. Bum’s obsession with Sangwoo reaches a point where he tries to break into his home.