The story opens with a description of the protagonist's identity. The protagonist explains that he is a metabaron, a kind of robot that has been missing from his master for three months. He tells the reader that his master once called him an initiator of the meta-warriors, a group of warriors who mutilate themselves in order to practice their martial arts. The metabarons were originally from a giant marble globe called marmola, which was surrounded by a small valley with a fortress called Castaka.