Mimirin Midorihara, a white anthropomorphic snowshoe hare, sports black-tipped ears, a pink nose, and a distinctive buck tooth. A pink ribbon decorates her left ear, a successor to her former red flower accessory. Her family’s florist business, Flower Shop Midorihara, sees her lending occasional help between attending Challenge Kindergarten, where she bonds with peers Shimajirō Shimano, Torippii Sorano, and Nyakkii Momoyama.

Gentle and naive yet prone to tears when opposed, Mimirin balances her spoiled, clumsy demeanor with unexpected bravery in forging friendships and tackling tasks diligently. Her passions span dolls, floral arrangements, and strawberry shortcake, while carrots repel her, and snakes, caterpillars, and insects spark fear. Despite her timid streaks, she outpaces all classmates in running.

Her visual evolution shifts from a yellow puffy-sleeved shirt paired with a red overall dress and light red shoes to a pink cardigan layered over a grey polka-dotted dress and Mary Jane footwear. The departure of childhood friend Ramurin leaves her as the sole central character without siblings, amplifying moments of solitude softened by kindergarten companions.

Collaborative adventures see her venturing into magical realms, confronting darkness by reclaiming a "Song of Courage," and evolving through shared challenges. Her bond with Shimajirō highlights reciprocal growth, as she aids him in overcoming shyness.

Ambitions to become a nurse, florist, or singer clash with her tone-deafness, while family dynamics spotlight parents Sota and Renge Midorihara—the latter embodying responsibility. The name "Mimirin" blends "ears" and "dignified," with "Midorihara" echoing "green field," a nod to her family’s trade. Character songs like "With a Wish..." underscore her narrative journey, weaving resilience into her whimsical world.