Heart Gear

Young teenage girl Roue lives a peaceful life with her "uncle", a gear named Zett. She spends her days exploring the ruins of the old world, destroyed by World War III two hundred years ago. During one of those explorations, she finds a strange cylindrical gear who calls himself Chrome, who for some reason doesn't have a "base program", which determines a gear's main purpose. Chrome may have to find that purpose himself in his new life with Roue and Zett…