Train: 1x3

Episode 3

Seo Kyung dies at the hands of the Mukyeong Serial Killer. Do Won realizes that this is the same culprit from the murder case 12 years ago. However, the more he investigates, the more mysterious things seem to get. Just as he is falling deeper into sorrow over losing Seo Kyung, Do Won sees someone at Mukyeong Station.