Chizuru Tachibana, a 24-year-old school nurse at Kawanuma East High, carries the moniker "Absolute Zero Tachibana" for her icy, impassive demeanor. Her striking appearance features short light grey hair with bangs obscuring her left eye, a petite 155 cm frame with a slender build and pronounced bust (87-56-85), and a work wardrobe of black tops, white lab coats, jeans, and heels. Off-duty outfits range from yellow sweaters with denim shorts to thigh-high stockings paired with athletic shoes. A distinctive physical trait—inverted nipples—becomes apparent under stimulation.

Though initially aloof toward students, she secretly aspired to mirror the warm, approachable nurses from manga. This longing drove her to reconnect with Koh Tanaka, a student from her hometown, after a chance reunion at a New Year’s event led to a joint trip to Ishigaki Island. Their travels sparked a series of comedic mishaps and growing mutual attraction. While she declined his Valentine’s Day confession to uphold professional ethics, she accepted his feelings post-graduation, recognizing their altered circumstances.

Their romance evolved through awkward attempts at intimacy, including an aborted encounter at a love hotel, culminating in marriage under the surname Tanaka and the birth of a daughter. Academically, she demonstrated balanced grades with strengths in math, science, and home economics.

Beneath her reserved facade lies a whimsical streak showcased through rapid costume changes, including Christmas-themed attire and striped thigh-highs. Her professional poise shines in crisis management and navigating embarrassing scenarios. Media adaptations diverge in depicting her swimsuit: floral in print, solid purple in anime.