It is the fate of the Hirasaka family to protect a barrier underneath Tokyo that separates the human world from the demons of another world. One day, an incident in the underground tunnels claims the lives of 6 civilians and a Hirasaka. The mass death and the mysterious circumstances under which it occurred have been hushed up by some powerful, but unknown, people. These people seem to be dismantling the barrier the Hirasaka family has fought so hard to protect, and it is up to the remaining Hirasaka to stop them.
