Yn survived a car accident that caused her mind to regress to a childlike state. Lost in the woods, she encounters the Slender Man who takes pity and heals her wounds. His true form is the tall pale entity, but around Yn he appears as a kind man named Rui Chen. Though hesitant at first, Yn grows close to her rescuers Rui and Jacob, unaware of their double life as the enigmatic forest stalkers known as the Slender Men.