A mysterious figure known only as the Storyteller appears at dusk wherever children gather. Wearing a yellow mask and carrying a wooden kamishibai stage on the back of his bicycle, he recites sinister tales drawn from Japanese urban legends and folklore. As his young audience listens, the Storyteller pulls illustrated paper scrolls through the traditional storytelling device, bringing his demented narration to life with jagged, deliberately crude animation that mimics the kamishibai style.

Each episode runs only about four minutes, presenting a self-contained horror story set in modern Japan. The opening episode follows a bachelor named Ito who moves into a new apartment and notices a single talisman stuck to his ceiling. After removing it, he becomes aware of a strange woman staring at him from across the street. When he returns from work the next day, his door is unlocked and another talisman has appeared. The woman is eventually arrested for breaking and entering, but when Ito returns to remove more talismans from his dining table, he looks up to find his room swarming with ghosts. Other early episodes feature a hospital patient trapped by whispering roommates performing a reversed banzai ritual called Zanbai, and a family that must laugh through the night wearing grotesque smiling masks to ward off an ancestral ghost.

The Storyteller serves as the series only recurring character across most seasons, though his true name and origin remain unknown. The third season introduces a different narrator, a boy who sits on a playground slide and sings while drawing illustrations of creatures from the stories. This boy is later revealed to be the Storyteller in child form, and by the season finale, his face transforms into the familiar yellow mask. Subsequent seasons return to the original Storyteller format but vary his setting, from telling tales in a forest to a dark apartment to a busy urban intersection surrounded by shadowy passersby. The ninth season features the Storyteller addressing animals representing the Chinese Zodiac, while the tenth season builds toward a finale based on the Hyakumonogatari Kaidankai, the traditional game of telling one hundred ghost stories. Each season follows a distinct theme, including female-focused horror in season five and stories about enclosed spaces in season seven.