"Skyhigh Karma" is a supernatural mystery manga that explores themes of life, death, and the consequences of one's actions. The story centers around Shou Kirishima, a young man who discovers he has the ability to see the "karma" of individuals, represented as a glowing aura around their bodies. This karma reflects the balance of good and evil deeds a person has committed in their lifetime. Shou learns that he is a "Reaper," a being tasked with guiding souls to the afterlife. However, his role is not merely to escort the dead; he must also judge whether a soul deserves to pass on to heaven or be condemned to hell based on their karma.

The narrative unfolds as Shou encounters various individuals, each with their own complex moral dilemmas and life stories. Through these interactions, the manga delves into the gray areas of morality, questioning the nature of justice and redemption. Shou's judgments are not always clear-cut, as he grapples with the weight of deciding the eternal fate of others. His own past and the circumstances of his death are gradually revealed, adding layers to his character and motivations.

Key characters include Rin, a fellow Reaper who serves as a mentor figure to Shou, and Aya, a human girl with a mysterious connection to the supernatural world. Rin provides guidance on the rules and responsibilities of being a Reaper, while Aya becomes a pivotal figure in Shou's journey, challenging his perceptions of life and death. The interplay between these characters drives the emotional core of the story, as they navigate the ethical complexities of their roles.

The plot is structured around episodic encounters with individuals whose fates Shou must determine, interspersed with overarching mysteries about the nature of the Reapers and the afterlife. The manga balances these episodic elements with a larger narrative arc, gradually revealing the truth behind Shou's abilities and the world he inhabits. Themes of forgiveness, accountability, and the human condition are woven throughout, creating a thought-provoking exploration of morality and the afterlife.