Hae Sung (Yeo Jin Goo) disappears after a mysterious accident. 12 years later, he wakes up on the roof of his school building. He is now 31 years old, but he still has the appearance and personality of himself at age 19 when he initially disappeared. He reunites with Jung Won, his childhood friend and first love. The two of them are now 12 years apart because Hae Sung was in another world. Hae Sung's siblings were all separated after his death, so he brings them together. He later finds out that he was unjustly accused of killing someone after he died. To solve the mystery of his death and clear himself of a false charge, he begins his own investigation. Accompany him on this dramatic journey to find out how he’ll get to the end of the road.