Kaneko Seika has moved from Tokyo to a high school in Sendai for a fresh start. She soon becomes fascinated by her mysterious desk neighbor, Washio Shiho, a quiet beauty with striking black hair and pale skin. Despite Seika's friendly efforts to get closer, Washio remains aloof and is often seen smiling mysteriously to herself. One day after school, Seika finds Washio alone in the classroom. As usual, Washio quickly flees, but this time she accidentally leaves behind a notebook, revealing a secret she had been hiding. From this moment, the true nature of the story unfolds, focusing on Washio and the groups of eccentric friends around her.

The manga is a youth comedy that originated from a popular segment of the radio show Nogizaka46 no All Night Nippon. The story centers on Washio Shiho, the titular character. The protagonist and primary point of view character is Kaneko Seika, a girl with strong social skills who becomes Washio's first real friend at school. The cast expands to include other classmates such as Ishino Muraame, a quiet girl who loves special effects, and Date Tohana, an enthusiastic devotee of the historical figure Date Masamune. Later, a rival character named Bon Tennshi appears, a relative of Date who insists she is the true reincarnation of Date Masamune.

Over the course of the narrative, the initially aloof Washio slowly begins to open up to her new friends. The series details their daily school life, including study sessions for exams and various humorous misunderstandings. A significant early arc involves Seika discovering that Washio harbors intense but secret interests, which is the core secret hinted at in the storys premise. The final volume introduces a major shift where the characters finally engage in a baseball match, bringing the sports element promised by the title to the forefront for the conclusion. The story emphasizes themes of friendship and the challenges of expressing ones passions without hurting others.