Willem Kmetsch, the last surviving human, wakes from a centuries-long petrification into a world where the remnants of civilization cling to floating islands above beast-infested land. Hired as a weapons caretaker, he discovers his charges are not arms but Leprechaun girls — among them Chtholly Nota Seniorious — who wield ancient swords called Carillons and are sent on missions they may not return from. Willem's knowledge of the old world is the only edge they have.