Girls' Last Tour Vol. 3 (manga)

The next phase of Chito and Yuuri's journey-- once they get their bearings-- brings them through unexplored territory where they encounter more mysteries about the people of old: huge automated facilities that once produced great quantities of food, a labyrinth of empty drawers, and a sparkling, bittersweet drink that makes the moon look especially lovely as it shines down on two lone wanderers in the abandoned ruins...