Hiemi lost her father to the Skull Clan's brutal murder, carrying the trauma of that crime ever since. As Saint Diamond, entrusted with protecting Earth and driven by vengeance for her father, she has relentlessly battled the Skull Clan. Finally infiltrating their hideout, she confronts the leader, Bloody Skull, and the Skull Demon—only to have them escape. After a fierce battle, Saint Diamond is captured and subjected to cruel experiments. The Skull Clan's ambition is galactic domination, to be achieved through cloning Saint Diamond. Though rendered powerless, she refuses to surrender. Here lies her answer—what she will do next.