The year is 40XX. A zombie virus broke out 60 years ago, and now only the Gogo Friends and you (or your group and the Gogo Friends) remain. Areum: There's a train over there! Let's go that way!! Mozzielle: Got it! Let's hurry!! Everyone boards, but someone has to get off. Baekhyun: Hey Guest! You get off. You're useless anyway, lol. Moyangmon: Huh? Why do they have to get off?? Pyeonghak: ..Guest, I'm sorry. He pushes Guest out of the train.