Yuichi, a boy with spiritual abilities, embarks on a journey alongside a cat spirit named Shou to find the notes left behind by his deceased master, Iroha. Haunted by a painful past, Yuichi has closed himself off from human connection, but as he travels through a world inhabited by humans and ayakashi, the warmth he encounters from both begins to thaw his guarded heart. The notes he seeks hold the message his master wished to leave him, a mystery that propels him forward.

The first volume follows Yuichi and Shou through various towns and encounters, each meeting chipping away at his isolation. In the second volume, the pair arrives at a town called Hyakutousen, which has for generations worshipped an eternal flame. As a festival to replace the lanterns approaches, a series of unexplained fires break out, caused by a rampaging fire spirit. Yuichi, who can see spirits, learns that the fire spirit was once one with a shadow spirit—an entity that attracts misfortune and is reviled by the townspeople. Confronting these opposing forces, Yuichi recalls his master’s words and begins to find light within his own shadows. The story weaves a bittersweet and beautiful tale of spirits, human struggles, and the gradual mending of a wounded heart.