The series is set on a gigantic, mysterious and seemingly endless train traveling through a barren landscape. Passengers on the train proceed from car to car by completing challenges which help them resolve their psychological trauma and emotional issues. The first season focuses on Tulip Olsen, a girl struggling with her parents’ recent divorce. The second season centers on the emancipated Mirror Tulip, now on the run from enforcers attempting to execute her as punishment for abandoning her role as Tulip's reflection.