In the beginning of 21st century, an atomic explosion in the South Pole caused a strange, unseen phenomenon: a black hole appeared and started spreading, threatening to swallow the Earth. It was named Schwarzwelt, or "black world". The United Nations send a team of four trained specialists from different countries to venture inside the Schwarzwelt. The protagonist is an unnamed Japanese soldier. Upon arriving into the Schwarzwelt, the team finds out that demons have entered the Earth.