Following Taizan and Onishiba into a Kimon portal, Riku and Kogenta end up in Tousa of Shikoku, where a local village's crops have been growing immensely. But the only crops worth of value are the mandarin oranges, which are owned by the Mikazuchi Group.
Riku and Kogenta then fight the Chi-ryuu Daikimon Construction Head, the elderly Nankai, and his Shikigami, Shuusui no Namazubou. Will Riku and Kogenta be able to defeat Nankai's 30-year bond with Namazubou?