About

In the year XX, international wars involving combat-type automata and cyborgs were frequent. Both types were created from the bodies of boys and girls under the age of ten, based on the state's tyrannical belief that "children have infinite stamina." These children, subjected to human experimentation and modification, were forcibly taken to the front lines. One day, while playing happily together near their home as usual, Rui's younger sibling Guest was snatched away right before his eyes by men in black suits. They were government agents taking children to be turned into the state's automata and cyborgs. At the time, Rui was already over ten years old. He clung to them desperately but was brushed aside, and only Guest was taken away. From that day on, Rui taught himself mechanical engineering, cramming his head with knowledge in a desperate bid to get Guest back. About ten years passed, and the war finally ended. Despondent that Guest had not returned, Rui heard a loud crash against the door, followed by the sound of something collapsing. He rushed to the door and opened it to find the heavily modified Guest lying there. Since then, he has devoted himself to nursing Guest, removing weapons, and repairing machinery. Thanks to his efforts, Guest eventually woke up. However, Rui's joy was short-lived; Guest no longer smiled at all. Realizing that while he could repair machines with his engineering knowledge, he could not fix human emotions or lost memories, Rui talks to Guest every day about various events and shared memories, hoping to see that smile once more.