High school senior Minami is bored. Convinced that she is destined to be the hero of her own story, she finds her everyday reality to be crushingly ordinary. This all begins to change when she discovers she might have actual superpowers. After trying to prove her abilities to her skeptical friend Nakamura by chanting a magical spell at a flower, nothing happens. However, a mug later shatters in her home under mysterious circumstances, planting the first seed of doubt. Her quest for proof escalates when she seemingly causes the windows of her classroom to explode and later performs a spectacular feat of levitating and manipulating rainwater into artistic, bubbly explosions across the city.

The story is set in a contemporary Japanese town and follows Minami, a dark-haired girl with a touch of amnesia from an incident in her past when she got lost during an elementary school hiking trip. Her close friend Nakamura is a protective presence who, while skeptical of the powers, supports Minami's unusual claims. The cast is rounded out by a young and innocent male teacher, Yamano, who attempts to ground Minami's fantastical experiences in scientific reality, even consulting a physicist friend who suggests her powers might involve gravity manipulation. Another key figure is Shimura, a fancy girl with long light hair who is initially presented as a haughty rival but soon reveals a more humble and complex personality, joining Minami's social circle.

Notable narrative arcs begin with Minami's initial struggle to prove her abilities to a disbelieving world, which leads her to disguise herself as Evolved High School Girl M for a television appearance, much to the chagrin of her teacher. A significant early conflict involves Minami taking responsibility after Shimura is injured by the shattering glass, leading to a confrontation with Shimura's overbearing, businesslike mother. This event unexpectedly triggers Minami's powers again, helping to mend the strained relationship between mother and daughter.

The story then moves from isolated incidents to a more deliberate exploration of Minami's powers. She and her friends plan a dream trip to New York, and she begins using her abilities for small, personal challenges, such as parting a river to walk across it, only for the power to run out and trap her. The first volume concludes with a jarring turn into the overtly supernatural when a talking deer appears at the riverbank. This deer, who learned to read and speak from a discarded language book, possesses its own powers of lightning and claims to suffer from the same sense of being othered as Minami. This encounter hints that Minami may not be a random girl who gained powers but rather that her powers and her forgotten past are connected to a larger, stranger world.