The mysterious giant underground labyrinth "Tartaros." There, adventurers day and night venture into They look for treasures and other riches. The rookie adventurer Rabi who challenged the dungeon "Tartaros" and who for his bad luck gets into some problems, it is at that moment when he met half-beast Philo, with whom he makes a deal to be his client habitual. What will happen to Rabi's adventure?