The World You See Isn't All There Is

Using Rei and Ibukimaru's techniques, and Cat-girl's life, a portal is opened to another dimension. Mana searches for Kitaro, racing into that place which is neither this world nor the other. Finally, she catches sight of Kitaro, but...!? Meanwhile, moment by moment, the earth is pushed closer to the tipping point by Backbeard. How will this war end, and will Kitaro return?!