After dying from heatstroke in modern Japan, a man with diverse hobbies including cooking, sewing, and musical theater reawakens as Ageha, the five-year-old eldest son of Count Kikunoi in the declining Kiou Empire. He is overweight, neglected by his parents who have not visited him in over a year, and known derisively as the white pig noble by the household staff. Using the wisdom from his past life, Ageha apologizes to the servants for his previous bratty behavior and begins exercising while learning their various jobs, gradually earning their genuine acceptance.

Ageha's life changes when his elf tutor, Aleksei Romanov, who secretly holds the title of Designated Imperial Hero serving directly under the Emperor, teaches him about the empire's corruption and his family's oppression of the peasantry. While singing daily in a hidden flower garden, Ageha attracts the attention of Princess Hyakka, the Goddess of Healing and Blessings, who unlocks his latent magical abilities and grants him the title Beloved of the Goddess. However, the goddess also demonstrates the ability to read his thoughts, creating an uneasy dynamic that his tutor closely monitors.

The central conflict emerges when Ageha meets his infant half-brother Regulus, whose mother has recently died. After witnessing his mother's butler push Regulus down a staircase, Ageha saves the baby's life but immediately receives a dark vision of an adult Regulus killing him over inheritance rights. Despite knowing this future, Ageha chooses to raise his brother himself when Romanov refuses to tutor the child. The initially timid Regulus proves to be sparkling and adorable, quickly turning Ageha into a doting older brother before he even realizes what is happening.

The narrative follows Ageha as he reforms his household and territory step by step. He introduces Japanese cuisine to the head chef, devises a plan for letterpress printing to educate the common people with help from Igor the God of Innovation, and begins establishing a company. Ageha also suffers from soul separation disease, a condition requiring him to strengthen his magic nerves, and Princess Hyakka gifts him a magical sage peach that he turns into sorbet. This sorbet later saves Maria Crowe, a future Imperial Court Singer, when she is poisoned during her debut performance.

Throughout the story, Ageha navigates complex family dynamics as the unwanted product of his mother forcing his father to abandon his true love. His parents remain distant and dismissive, with his father bringing Regulus primarily for Romanov to tutor rather than out of care for either child. The narrative balances heartwarming sibling bonding with political intrigue, divine intervention, and Ageha's quiet determination to prepare Regulus to become a worthy lord, even as Ageha suspects he may not live a long life. The series explores territory management, cultural diplomacy, and the gradual reformation of a corrupt noble household through the perspective of a child protagonist armed with adult memories and unconventional skills.