In 1983, high school teacher Ji-hwan is attack by a cutpurse. In 2015, homicide detective Gun-woo is shoot during a pursuit and lose consciousness. Both men are take to the same infirmary in different clip time period, and both their Black Maria halt and miraculously get down once again at the same clip. A cryptic force adhere them together, let them to see through each other’s life in their dream.