In a secluded coastal village in Japan, Hiroto's world revolves around the enigmatic Yokohama Station, a colossal structure that has devoured much of the surrounding land. The station, shrouded in myths and mysteries, becomes accessible to Hiroto when he obtains an 18 Ticket, granting him a five-day passage into its depths. As he ventures Inside for the first time, Hiroto's quest for meaning takes a profound turn, unveiling a purpose he never anticipated.