Kozame-chan is a young anthropomorphic shark defined by her childlike curiosity as she explores everyday experiences. Her adventures unfold primarily within Yauo Town, a setting evoking nostalgia through depictions of seasonal activities like summer cider, freeze pops, radio calisthenics, and festival stalls. She communicates primarily through expressive vocalizations and non-verbal sounds rather than conventional dialogue. These vocalizations, often described as "gibberish" or represented symbolically (e.g., "◯▲☆■～"), convey emotions from excitement to wonder. Despite this unconventional communication, she sings the ending theme song "Yorimichi," whose lyrics emphasize optimism and discovery: "Even on a clear day, Even on a rainy day, Let's look for new things" and "When it's done with a smile, It's gonna be a beautiful world!" Her design utilizes a simple, cute aesthetic intended to create a calming and heartwarming impression. This visual approach supports her role in depicting small, joyful moments such as eating ice cream, seeing a rainbow, or assisting other characters, like helping a friendly frog cross a bridge. Her expressions and reactions are central to conveying the simplicity and positivity of these experiences. Kozame-chan interacts with a recurring cast including Ankō-chan, Usame-chan, a man with a mohawk ("Mohikan Aniki"), Haruto, Sora, and Miho. These interactions often highlight her innocent perspective on the world. A special Halloween visual depicted her wandering streets at night, indicating her adventures extend beyond daylight hours.