A l'Era Taisho, en Tanjiro Kamado és un noi intel·ligent amb un bon olfacte i cor que vivia amb la seva família a les muntanyes i guanyava diners venent carbó, però tot canvia quan la seva família és atacada i assassinada per un dimoni (oni). En Tanjiro i la seva germana Nezuko són els únics supervivents de l'incident, tot i que la seva germana Nezuko es converteix en un dimoni. Sorprenentment, però, encara mostra signes d'emoció i pensament humans. Després d'una trobada amb en Giyu Tomioka, un caçadimonis, en Tanjiro és reclutat per l'Urokodaki per a convertir-se també en un caçadimonis. Així comença la seva cerca per a ajudar la seva germana a tornar-se humana novament.
In a world inhabited by people only a few inches tall, young women Hakumei and Mikochi live together in a house built into a tree. Hakumei is an energetic and tomboyish carpenter, while Mikochi is a feminine and calm tailor. Despite their differences, they get along well and spend their days having fun living their lives in the woods.
The two of them spend their time working, going on sightseeing adventures, and taking shopping trips into Tsumiki Marketplace by the ocean. They make many friends along the way, be they sentient woodland creatures like Iwashi the Weasel or fellow miniature people such as the songstress Konju and the inventor Sen.
This is a relaxing look into the day-to-day lives of its titular characters as they explore and interact with their tiny world which seems to be straight out of a fairy tale.
