"Tsundere Inran Shōjo Sukumi" centers on the life of Sukumi, a high school girl who embodies the classic tsundere archetype, characterized by her outwardly cold and abrasive demeanor masking a deeply affectionate and caring personality. The narrative explores her struggles with expressing her true feelings, particularly toward her childhood friend and classmate, Haruto. Despite her harsh words and defensive attitude, Sukumi harbors a strong romantic interest in Haruto, which she finds difficult to articulate due to her fear of vulnerability and rejection.

The story unfolds in a school setting, where Sukumi’s tsundere tendencies often lead to comedic misunderstandings and awkward situations. Her interactions with Haruto are marked by a push-and-pull dynamic, as she alternates between berating him and subtly attempting to show her affection. Haruto, on the other hand, is portrayed as kind-hearted and patient, often tolerating Sukumi’s outbursts while remaining oblivious to her true feelings. This dynamic creates a recurring tension that drives much of the series’ humor and emotional moments.

Supporting characters include Sukumi’s classmates, who serve as foils and catalysts for her development. Among them is Yui, a cheerful and outgoing girl who openly expresses her feelings for Haruto, creating a love triangle that further complicates Sukumi’s attempts to confess her emotions. Another key figure is Riku, Haruto’s best friend, who often teases Sukumi about her behavior but also provides occasional advice, highlighting her internal conflict.

The plot progresses through a series of episodic scenarios, each focusing on Sukumi’s attempts to navigate her feelings and relationships. These episodes often involve misunderstandings, comedic mishaps, and moments of introspection, gradually revealing her softer side. As the series progresses, Sukumi begins to confront her insecurities and learns to communicate more openly, though her tsundere tendencies remain a defining aspect of her character.

Themes of self-acceptance, emotional vulnerability, and the complexities of young love are central to the narrative. The series balances lighthearted humor with moments of genuine emotional depth, offering a portrayal of a character archetype that is both relatable and endearing. Through its exploration of Sukumi’s journey, "Tsundere Inran Shōjo Sukumi" provides a nuanced look at the challenges of expressing love and the growth that comes from embracing one’s true self.