In an unknown place, there is a train station called by "Sweet Rendezvous". The train station only provides one train, with one way route. Only chosen people with unforgettable sorrowful past can come to this place. They believe that the train will bring them to a safe place-- where they will start a new life without their heart-aching memories haunting. 

And Kim Myungsoo is one of the chosen people.

one way ticket; myungyeol; pg; AU