Hibiki Amami is the central character of her story, a high school girl who possesses an extraordinarily strong sixth sense, a condition known in Japanese as "re-kan". This ability, which she inherited from her late mother, allows her to see, hear, and physically interact with ghosts and other supernatural beings. She is a transfer student beginning her first year at Hanazuka Public High School. Her upbringing was unique; her mother Yuuhi passed away when Hibiki was born, leaving her to be raised solely by her father, Asahi. Asahi is a kind man who is deeply frightened by the supernatural, a trait that was so amplified by his wife's abilities that his hair turned white shortly after meeting her.

In terms of personality, Hibiki is defined by her profound kindness and gentle nature. She is described as polite, slightly air-headed, and possesses a saintly level of compassion, often worrying more about the well-being of those around her than about herself. She embodies the qualities of a yamato nadeshiko, the archetype of a woman who displays traditional Japanese feminine virtues. What truly sets her apart is her inclusive and accepting worldview; she treats spirits not as frightening entities to be avoided, but as friends who deserve the same respect and care as the living. This unconditional kindness is her primary motivation, as she consistently seeks to help any ghost in need, whether by listening to their problems, offering them food, or helping them find peace.

Her role in the story is to serve as a bridge between the world of the living and the world of the dead. Her daily life at school becomes a series of gentle, often comedic, adventures through which the existence of the supernatural is revealed to her friends and classmates. She makes no distinction between her relationships with the living and the dead. Among her spectral companions are a samurai warrior who died of starvation and now serves as her loyal protector, the ghost of a girl named Hanako who haunts the school's bathroom, the earthbound spirit of a park, and a perverted cat with a one-track mind.

Key relationships shape her world. Her relationship with her classmate Narumi Inoue is particularly important. Narumi is terrified of anything occult and vehemently denies the existence of ghosts, which creates a frequent source of friction and comedy. Despite her fear, Narumi is drawn into Hibiki's orbit and the two develop a close, if often strained, friendship. Hibiki's other friends at school, including the occult-blogging Kana Uehara, the former delinquent Kyoko Esumi, and the zombie-obsessed Makoto Ogawa, form a supportive group that accepts her unique abilities as a matter of course. Her family life with her easily-frightened father, Asahi, further grounds her story in warmth and humor. Her kindness also influences the ghosts she meets, as they become fiercely protective of her in return for her care.

Throughout the narrative, Hibiki herself shows subtle development, primarily through the deepening of her bonds with both her friends and spirits. While her core nature remains unchanged, her interactions highlight a recurring theme of the need for connection and acceptance, often pulling the more cynical or frightened characters like Narumi into a more empathetic worldview. The emotional weight of her ability is most apparent in her connection to her late mother, a link that provides poignant moments of familial love that transcend death.

Notable abilities extend beyond simple sight; she can communicate with animals, which she demonstrates by talking to cats, and her sensitivity to the supernatural is so acute that her walk to school can be significantly delayed by the sheer number of invisible people she stops to converse with. Her actions inadvertently allow ghosts to be photographed on her friends' cell phones, offering proof of the invisible world that coexists alongside the ordinary one.