"Nanoka no Kare" centers on Nanoka, a high school girl who finds herself entangled in a supernatural predicament after a chance encounter with a mysterious boy named Subaru. Subaru, who appears to be an ordinary student, is revealed to be a "shinigami," a being tasked with guiding souls to the afterlife. Their lives become intertwined when Nanoka accidentally interferes with Subaru's duties, leading to a series of events that disrupt the balance between life and death.

As the story progresses, Nanoka discovers that her actions have unintended consequences, including the appearance of malevolent spirits and the destabilization of the boundary between the human world and the afterlife. Subaru, bound by his responsibilities, must navigate the complications caused by Nanoka's involvement while also grappling with his growing attachment to her. The narrative explores themes of mortality, duty, and the complexities of human emotions, as both characters confront their own fears and desires.

The relationship between Nanoka and Subaru evolves from one of reluctant partnership to a deeper connection, as they work together to resolve the supernatural disturbances caused by their intertwined fates. Supporting characters, including other shinigami and humans affected by the supernatural events, add layers to the story, highlighting the ripple effects of Nanoka and Subaru's actions. The manga balances moments of tension and action with introspective scenes, creating a narrative that is both emotionally engaging and thematically rich.