After a great adventure over the giant moving weapon ‘Gualacuna Fortress’ Avaro finally acquires a workshop he once dreamed of, but fortress can not move on its own anymore with the magic in its core lost. One day a ghost of the fortress appear, Fia calls her "Kuna" and welcomes to the family. However, spirit is constantly worried about magic anomality on the north-eastern border. So our heroes decide to spend honeymoon investigating the source of trouble.

[From vndbreview]