Go Yi-Young, a mystery game enthusiast, is walking down the street while leaving a review for the popular mystery game The Sin of the Blue Silhouette when he fails to avoid a bicycle and gets hit by it. When he regains consciousness, he realizes that he has entered the mystery game he was playing just a moment ago, and in order to survive, he tries to prevent the murder of the culprit he saw in the game, Cha Gyeon-Woo...

(Source: Bomtoon, translated)