"Sasameki Koto" is a romantic comedy anime series centered on the relationship dynamics between Sumika Murasame and Ushio Kazama, two high school girls navigating their feelings for each other. Sumika, a tall and athletic student, harbors a deep romantic affection for her best friend, Ushio, who is petite, cheerful, and outgoing. However, Ushio is openly a lesbian and frequently expresses her admiration for "cute girls," yet fails to recognize Sumika's feelings or her own potential attraction to her. This creates a bittersweet tension as Sumika struggles to confess her love, fearing rejection and the potential loss of their close friendship.

The story unfolds within the context of their daily lives at school, where they are members of the karate club. Sumika’s internal conflict is further complicated by Ushio’s obliviousness and her tendency to flirt with other girls, often leaving Sumika feeling overlooked and frustrated. Despite this, their bond remains strong, with Sumika often supporting Ushio in her endeavors and Ushio relying on Sumika for emotional stability. The series explores themes of unrequited love, self-discovery, and the complexities of relationships, blending moments of humor with poignant emotional undertones.

Supporting characters, such as Tomoe Hachisuka and Miyako Taema, add depth to the narrative. Tomoe, a classmate and friend, becomes aware of Sumika’s feelings and occasionally offers advice, while Miyako, a younger student, develops a crush on Sumika, creating a secondary love triangle. These interactions highlight the challenges of communication and the misunderstandings that often arise in romantic relationships. The series maintains a lighthearted tone while addressing the emotional struggles of its characters, offering a nuanced portrayal of love and friendship in a high school setting.