"Kaya-chan wa Kowakunai" centers on Kaya, a young girl who possesses an unusual trait: she is completely unafraid of ghosts, monsters, and supernatural phenomena. This fearlessness sets her apart from others, as she navigates a world filled with eerie occurrences and paranormal entities. The narrative unfolds in a series of episodic encounters where Kaya interacts with various supernatural beings, often turning what would typically be terrifying situations into lighthearted or comedic moments due to her lack of fear.

The series explores Kaya's daily life, blending elements of horror and comedy as she encounters ghosts, spirits, and otherworldly creatures. These entities, often expecting to frighten her, are instead met with her calm and curious demeanor, leading to unexpected outcomes. Kaya's interactions with the supernatural are not limited to mere encounters; she often helps these beings resolve their lingering issues or misunderstandings, showcasing her compassionate and problem-solving nature.

Supporting characters include Kaya's friends and family, who occasionally find themselves caught up in her supernatural adventures. While they are often terrified by the paranormal events, Kaya's presence provides a sense of security and humor. The series balances its horror elements with a comedic tone, emphasizing Kaya's unique perspective and her ability to humanize even the most fearsome creatures.

The episodic structure allows for a variety of supernatural scenarios, each highlighting different aspects of Kaya's character and the world she inhabits. From haunted houses to cursed objects, the series delves into a wide range of folklore-inspired tales, all while maintaining a focus on Kaya's fearless and kind-hearted approach to the unknown. The narrative avoids heavy drama, instead opting for a lighthearted exploration of the supernatural through Kaya's eyes.