Four immortal young women divide their time between ordinary student lives and dangerous secrets. In a future Manhattan, Kate, Rose, Rachel, and Claire go to school by day and work as bounty hunters at night. After a successful hunt, two transfer students, the fragile Louise and her handsome older brother Edgar, approach the group and seek their friendship, though their motives are unclear. Soon the girls' old ties to Roosevelt Island, the cursed Red Garden where they were reborn, return to haunt them, and they must face both their past and a deadly present enemy. This one-episode OVA mixes mystery with mecha elements.