Within the Public Security Intelligence Agency (PSIA) of Japan, there exists a secretive group of federally funded military assassins known as Executors. This organization's goal: Prevent the end of the world, and even the entire universe. Magic exists in public knowledge in the form of magical girls: Women and girls born with a strange genetic mutation that allows them to perform feats of impossibility through sheer force of will alone by exploiting a glitch in the universe's construction. These girls, when corrupted by overuse, threaten to bring an end to all life through their unconscious will. Seven is an Executor tasked with killing these girls and investigating the sudden appearance of a cult which wishes to bring about this end, and this is her story. Follow her as she uncovers the identity of the mysterious "Iris of Death" and learns the purpose of their existence.