The angel Alexiel loved God, but she rebelled against Heaven when she saw how disgracefully the other angels were behaving. She was finally captured, and as punishment sent to Earth to live an endless series of tragic lives. She now inhabits the body of Setsuna Mudo, a troubled teen in love with his sister Sara. Setsuna's misery mirrors the chaos among the angels, and their combined passions threaten to destroy both Heaven and Earth.
As the pieces fall into place, High Angel Rosiel's master plan becomes clear. With Lucifer under his control, he intends to enter Atziluth, the highest plane of Heaven, through the Gate of the Grand Cross and take control of the Tablet of Heaven, an object that can grant all wishes. Aware of Rosiel's plan, Setsuna and the other angels race to the Gate to stop Rosiel from bringing about the destruction of the world. But the closer they get the more they see that Lucifer may have his own reasons for entering the Gate.