"Total Eclipse of the Eternal Heart" is a supernatural romance manga that intertwines themes of love, fate, and the afterlife. The narrative centers on Mikuni Kakeru, a high school student who has the ability to see ghosts. This ability isolates him from others, as he struggles to navigate a world where the living and the dead coexist in his perception. One day, Mikuni encounters a mysterious boy named Shougo, who claims to be a ghost but behaves unlike any spirit Mikuni has ever met. Shougo is cheerful, carefree, and seemingly unaffected by his ghostly state, which intrigues Mikuni.

As the story progresses, Mikuni learns that Shougo is not an ordinary ghost but a "guardian spirit" tasked with protecting him. The two form a close bond, with Mikuni finding solace in Shougo's presence despite the complications it brings to his life. However, their relationship is complicated by the revelation that Shougo's existence is tied to a tragic event from Mikuni's past. Shougo’s true identity and the circumstances of his death are gradually uncovered, revealing a deeper connection between the two that transcends time and memory.

The plot explores the emotional and psychological toll of Mikuni's ability, as well as the moral dilemmas surrounding life, death, and the choices that define them. Supporting characters, such as Mikuni's classmates and family, add layers to the story, highlighting the contrast between Mikuni's isolated world and the normalcy of those around him. The narrative builds toward a poignant exploration of love and sacrifice, as Mikuni and Shougo confront the inevitability of their separation and the impact of their bond on both the living and the dead.

The manga balances moments of lighthearted humor with darker, introspective themes, creating a nuanced portrayal of its central relationship. The supernatural elements serve as a backdrop for the emotional core of the story, which focuses on the characters' growth and the bittersweet nature of their connection. Through its exploration of memory, loss, and the enduring power of love, "Total Eclipse of the Eternal Heart" delivers a compelling and emotionally resonant narrative.