After transferring to Junekan High School located in a rural town of Northern California, 16 year-old Hope Lida starts a new life by living with her uncle and her niece, and quickly making new friends. Shortly afterwards, Hope and her friends stumble into a strange dark labyrinth filled with gravitational stairs by going through a display door located at the home improvement section at a local department store. The group realizes a connection between the dark world and reality, and they decide to fight back mysterious creatures known as "Black Orbs", preventing them to cause danger to the town, while seeking aid with an orange kangaroo.