Tokyo in the near future. People live in the sky to avoid disasters and epidemics. However, this is only for the rich, and the poor still live underground. In order to cure his sister Mari's incurable disease, Nounai Senri joins the giant pharmaceutical company RUOWA, where he takes RUOWA Metal, a drug that turns muscle into metal, and begins to suffer from side effects. He starts working to kill people who suffer from the same side effects.