Train

Dead bodies in skeleton form are found in closed down Mugyeong Station. Do-won is on the case.

Seo-kyung finds the keepsakes that were gone 12 years ago at a murder scene in the skeleton.

Seo-kyung is murdered by the Mugyeong Station killer. Do-won sees someone unexpected at the station.

Do-won goes to World B and meets Seo-kyung. He's being chased as the suspect of a murder case.

Do-won A starts looking for victims of World A in World B, then has an unexpected encounter.