In a world constantly devastated by thousands of monsters, only a small part of humanity (individuals unable to use magic or naturally defend themselves) managed to survive. Those few were only capable of doing so by developing multiple technologies: that no knight or warrior could ever dream of. Thus, seing the ammount of effort the vulnerable little humans have made to stay alive, the goddess "Saga", one of the most powerfull beings to ever exist, made a contract with man to aid them: she would imprision all monsters on a enormours tower, giving, at last, peace and tranquility for the humans. But, it had a price. If, in a hundred years , they did not manage to reach the top of the tower; a reality worse than the one which used to happen to them would fall onto the world. Now the weak humans work day and night to improve and advance upward to reach the top!