A ruined world where mechanical bodies known as "Avatars" are becoming widespread. Ao, a girl living in the lower levels of the city, barely scrapes by each day working as an Avatar mechanic. One day, in a back alley, she finds an Avatar girl named Ariadne in a battered state. Unable to just leave her be, Ao repairs her, but as soon as Ariadne wakes up, she kisses Ao and says, "Let's get married..." Girls living at the bottom of the world. Their "everyday life" slowly begins to sparkle.