In a world blending Western and Eastern influences, Ageha, the sole heir to Count Kikunoi in the Kiryuu Empire, faces a bleak future from the tender age of five. Born in a distant region, he lacks allies and practical skills, and his weight adds to his vulnerabilities. Complicating matters further, his brother Regulus, who abruptly enters his life as the Count's other son, seems destined to challenge Ageha's claim to the inheritance.
Despite these challenges, Ageha acquires unexpected skills in cooking and sewing alongside memories from a previous life in Japan. As he takes on the role of caretaker for his younger sibling, he discovers an irresistible affection for his adorable brother: "My baby brother is incredibly cute!" Soon, he becomes a devoted older brother, crafting educational toys and preparing delectable chawanmushi for his cherished child.
Harnessing his newfound talents and domestic prowess, Ageha works to enhance the lives of those under his stewardship. This fantasy tale follows the duo as they navigate their responsibilities and transform their surroundings, with every decision potentially influencing divine intervention and reshaping their nation.