As a magic wielder, young archivist Chakuro knows his time is short, but everything changes when a girl from the outside appears on his island. Chakuro’s peaceful life on the Mud Whale is interrupted by the appearance of another island. When they investigate, he finds a girl living there. The rebellious Ouni takes Chakuro and Lykos back to her island. She explains that she’s an Apátheia, a soldier who’s lost her emotions. The Mud Whale is invaded by the ruthless and mysterious troops of the “Empire.” Using magic, Ouni and some of the others begin fighting back.