In the year 199X, mankind faces extinction due to frequent calamities like abnormal weather or huge insect swarms, caused by the power of the demons. However, Rosa, a woman with mysterious powers appears. Not only does she drive back all disasters, she is also revered as the savior of the world. The demons' leader, Demon, is not happy with this. For the sake of his plan to wipe out humanity, he starts the activation of the Tower of Babel, something which causes his life to be targeted by Rosa. On the other hand, Rosa has started the construction of the Tower of Cain. Now an all out battle which will decide the destiny of mankind begins..
(Source: Rough translation of the Japanese summary on Wikipedia)