In the realm beyond death, souls continue their journey toward enlightenment, navigating through various levels of the spirit world to refine themselves. Some are reincarnated, while others become guardian spirits for the living, shielding souls from the darkness that lurks below. Riyon, a carefree spirit known for her lackadaisical approach to spiritual training, is tasked with a new role as a guardian spirit. Rather than accompanying a newborn, she aids the ailing Japanese Prime Minister, Kasuga Soichiro, in his final eighteen months. As Kasuga faces a brush with mortality, he gains extraordinary abilities, including the rare gift of seeing Riyon. Can this unconventional duo safeguard Kasuga's fragile soul amidst looming threats?