Koi wa Futago de Warikirenai

Jun Shirasaki has always been close to the twin sisters who live next door, Rumi and Naori Jinguuji. Though they're twins, the sisters couldn't be more different. Rumi, the older sister, has a boyish appearance but a sweet, maiden-like personality, while Naori is a super girly and passionate otaku. As Jun grows up, he finds himself entangled in a complicated love triangle with the two sisters, each pulling his heart in different directions.

Jun's relationships with Rumi and Naori become increasingly complex when Rumi, who was his first girlfriend, breaks up with him. Her words during the breakup leave Jun in a state of confusion and longing, complicating his feelings for both sisters. As the trio navigates their intertwined lives and emotions, they must confront their first loves and the changing dynamics of their relationships.