A serial killer ruthlessly hunts down a deaf woman through the streets of South Korea after she witnesses his brutal crime.
A homeroom teacher of Yosan Private High School has an accident, and thus a substitute comes to fill in. Han Bong-Gu is a mysterious man, and after strange occurrences the class president Ye-Rim tries to get to the bottom of this mystery.
Childhood friends reunite; hidden secrets emerge, threatening to shatter their bond and expose painful truths that could end their friendship.
