In the Land of Leadale, Vol. 6 (light novel)

High elf adventurer Cayna was exploring a dungeon and reached the lowest floor where she was reunited with Opus, an old friend from her gaming days. Their reunion was short-lived, however, since Cayna immediately lost consciousness after suddenly exhausting her magical power. Opus takes Cayna and her companions Clofia and Cloffe to his hideaway to rest and recover while he prepares for an imminent event, but what exactly is he so busily preparing for...?