Nitroplus Gekijou: Sumaga - Adult Channel

The protagonist regains his consciousness to find himself falling down from the sky. As he realizes that he doesn't know why he's here, even more, that he doesn't remember anything at all, three girls flying on brooms appear in front of him. Shortly after as he keeps falling he witnesses a tragic battle between these girls calling themselves Etoile and the monsters they call Zodiac to take place.