I was caught off guard with this drama. I don't know how many parallel worlds they were focused on by the writers. I became so confused. I need to watch it again so I can see what the heck who is who. I watched it all, just didn't seem long enough for me. I'm used to watching 16-21 episodes in a Kdrama. The actors and actresses were all great but gave it 8 this time because they tried hard to represent the storyline. The idea of a train going back n forth into the different worlds was unique. I apologize.