"Madowasenaide Yamori-kun" centers on the life of Yamori, a high school student who becomes entangled in a series of supernatural events after encountering a mysterious girl named Yuki. Yuki is revealed to be a spirit bound to the mortal world, seeking to resolve unfinished business. Yamori, initially reluctant, is drawn into her world as he discovers his own latent ability to perceive and interact with spirits. This ability becomes both a burden and a tool as he navigates the challenges posed by malevolent entities and the complexities of Yuki's past.

The narrative unfolds through episodic encounters with various spirits, each with their own unresolved issues tied to the human world. These encounters often explore themes of regret, loss, and redemption, as Yamori and Yuki work together to help these spirits find peace. Alongside these episodic arcs, a larger plotline emerges involving a shadowy organization that seeks to exploit spiritual energy for its own purposes. This organization becomes a recurring antagonist, forcing Yamori and Yuki to confront increasingly dangerous threats.

Yamori's character evolves from a passive observer to an active participant in the spiritual realm, driven by a growing sense of responsibility and empathy. Yuki, on the other hand, grapples with her own fragmented memories and the emotional weight of her unresolved past. Their dynamic is marked by mutual dependence and a deepening bond, though their relationship is often tested by the moral dilemmas and dangers they face.

Supporting characters include classmates and acquaintances who become aware of Yamori's abilities, some of whom assist him in his endeavors while others serve as foils or obstacles. The series balances moments of tension and action with quieter, introspective scenes that delve into the emotional stakes of the characters' journeys. The interplay between the human and spiritual worlds is a central focus, with the narrative frequently exploring how the two realms intersect and influence one another.