Deep within a frontier cave stands the Labyrinth's Essence Cup. It is said that by filling it with magical energy, one can obtain immense power. Inside this labyrinth, magic operates under a special law: the stronger your futanari member, the more powerful your magic; and the larger your breasts, the more spells you can unleash. Magical power dwells within sexual functions. In other words, filling the Essence Cup with magic means... continuously offering futanari fluids to the cup.