Ninja and animal lover Jiro Azuma’s life is changed forever when he finds himself in the middle of a war with ninjas vs. demons. Jiro Azuma is descended from of a long line of shinobi, and he also can talk to animals. One day, he rescues a very unique black cat named Rago, a supernatural being, and is dragged into a secret supernatural war. Although he may appear rough-and-tumble, Jiro Azuma’s compassionate side emerges when it comes to the furry critters he can communicate with. But Jiro's soft spot for animals gets him in major trouble when a suspicious stray cat fuses with him, granting him exceptional power but also dragging him into humanity's hidden battle against powerful Japanese spirits, mononoke.

対物ノ怪特別機動隠密部の新部隊、通称「黒の灯火」の一員となった我妻弐郎！　だが、更なる入隊者・桐原零司は、物ノ怪・羅ゴウと同化した存在の弐郎に猛反発。敵対する二人に、課長の司場は真剣勝負を命じる。やがて初任務へと向かった「黒の灯火」。そこは、羅ゴウが封印されていた地下施設だった…！！

妖術対抗訓練の中で見せられた幻覚の世界で、羅ゴウと弐郎は物ノ怪・天鬼と遭遇。時は江戸時代、幕府の物ノ怪狩りに対抗するため、天鬼は羅ゴウへ共闘を持ちかけるも拒絶され、逆に羅ゴウを追い詰める──。殺生石に封印された羅ゴウの秘密とは！？　そして訓練終了後、街では連続怪死事件が…！！

Ninja and animal lover Jiro Azuma’s life is changed forever when he finds himself in the middle of a war of ninjas vs. demons. Jiro Azuma is descended from of a long line of shinobi, and he also can talk to animals. One day, he rescues a very unique black cat named Rago, a supernatural being, and is dragged into a secret supernatural war. In order to save Jiro’s life, Rago pledges loyalty to Amagi, his mortal enemy! But Rago has no intention of letting his power be used by evil forces, and so when he joins Amagi, he leaves all his power behind in Jiro. Outraged at the unexpected betrayal, Amagi unleashes his wrath upon Rago!

同胞を欺き、力でこの世を支配しようと企む物ノ怪・天鬼。最後に狙うのは、弐郎の中に残された羅ゴウの力。弐郎は天鬼との対決に向け、己の中の妖力と対峙するが、絶大な力を制御できる時間は、ごく僅かと知る。隠密局は総力を結集、弐郎のバックアップ態勢を固める。羅ゴウ救出を誓い、弐郎は単身、天鬼の元へ！　長い戦いの歴史に終止符が！？　怒濤の最終巻！！